James has things pretty much spot on. If 14 year-old Joey has a simple phone app that plays tic-tac-toe, then a small change might be accomplished in an hour, however, with any major, commercialized application there are several required processes and far more time involved. How much is a factor of all the various areas that need to be involved.
[Point made. Feel free to skip the rest and go on with your life if you wish or, dive into far more depth on the topic! LOL!]
Some of what is involved depends on what software project management methodology the company itself adopts. The older style (called "waterfall" and promoted by the Project Management Institute or PMI) works well with big projects where releases happen less frequently. Microsoft releasing a new OS every two years would fall under this type. In this style any change, regardless of size, gets lumped together and you'll see a long change log when it finally comes out. The newer approaches (of which there are several, like Agile and Scrum) have small, incremental releases. Each has its own benefits and detriments, but with the new online approaches and lifetime updates, the newer styles are pretty much the winners now. Needless to say, this is a tiny summary that doesn't include many of the other methodologies that are more used for other types of production (Adaptive, Critical Path, Six Sigma, etc.) and doesn't touch on the newer ways software becomes available to the consumer like Software As A Service (SAAS - where you pay a monthly fee to access the software online like Office 365). The bottom line here is that the newer approaches will have the small change you want faster but, in all real companies, there are project managers and many other people that get paid a lot involved.
Once the project managers, in conjunction with business analysts, user experience people (UX), some upper management and, maybe, a steering committee decide on what new changes and fixes will actually become included in a release, then scheduling and resource allocation can occur (this is done between the project managers and programming managers). The programming managers will then assign the work to the programmers, database administrators and analysts who do the design and coding along with unit testing. From there the new and/or revised modules are sent to a Testing team who tries to break both the individual modules as well as the whole system (obviously there can be some loops back to development when errors are found). Once the software passes it usually goes to an Architecture or Integration group who then prepares and packages the software (not physical packaging) for release. Of course, during the time that the programmers and analysts are creating the code, there are other departments busy creating or updating the look of the product (if this will be sold in a physical package, then that's part of this too). These departments include graphic designers, web designers and developers as well as website administrators. Printing and distribution companies (suppliers) are brought in here too.
Think that's enough people involved? Well, there's more. Depending on the company, you'll also have people dedicated to Change Management and Quality Control (which usually operate in-between the testing and architecture/integration teams), a training team (who, along with the graphic designers, create the user's guides, manuals, maybe tutorial videos or commercials), a technical support team (to answer all your burning questions in Hindu - just kidding, I think) and the sales team! Because, what good is a product if nobody sells it? Now, for a lot of this these days it's the creation of ad copy for the web or videos, but there's still plenty of in-person effort at stores that will sell the product or working demo booths.
Are we done? Not even close! There are also several departments that keep the company going. These include Human Resources (HR), Accounting, Executive (including all the "C" level people, Administrative Assistants and Receptionists), Infrastructure (internal sysadmins, networking, server managers and technical support), Legal and last, but certainly not least, Facility Management.
Heck, since this was all off the top of my head I probably left some groups out! LOL. Throughout my career, I have in some small way or very large way done almost ALL of the above at one time or another (except HR, Legal and Facility Management).
Obviously smaller companies don't handle all of these areas by themselves, and some people will do multiple positions (I've worn as many as 17 hats during the start of a new alternative energy business - think 90+ hour work weeks with jobs still not getting done until we could hire more help!). A company can also outsource many of these areas (Legal, Accounting, Infrastructure, Graphic & Web Design) and/or use consultants as needed (Project Management, UX, Programming, Business Analysts, etc.). Even the unpaid public can be used in the form of Beta testers (their reward is seeing things first and self-gratification). Heh, I just thought of another group that they may have: Data Warehousing. Which, with Business Information (BI) specialists, can help the executives examine historical data and determine patterns for future products or enhancements (so-called Data Mining).
Now, ALL of the people in these groups have one thing in common: They like to be paid! So any change needs to make sense from an ROI (Return On Investment) point of view. While this may usually be profit directly, it can also be in the form of brand promotion or enhancing a company's integrity/perceived value which, if done correctly, still goes back to profit. By far, the fastest any change will happen, will be in response to a major product failure that was somehow missed by all the Testing, CM/QA and Architecture/Integration teams. Even this will take far longer than an hour though.
I bet you weren't expecting that much when you asked your questions (and I sure wasn't expecting to write this much! I should have started with "Hi," ya?
). I won't blame you if this becomes a tl;dr post, but it should explain why things take so long to be done and why it costs what it does.
