I don't understand why Cakewalk can't program new effects and plugins to automatically replace older ones when we upgrade to new versions of Sonar...at least in producer. Every time I upgrade and open older projects recorded in previous versions of Sonar I have to manually implement the replacement plugins and effects like reverb, compression, etc. Am I missing something or is this just the way it is? Seems like a net trade off for every time saving enhancement in the new version there's the time wasting replacment of plugins and effects.

It is unrealistic to expect some future DAW will work with the current set of plug-ins. It is unclear which of the missing plug-in issues you are experiencing; completely missing plug-ins due to 32 to 64bit migration, the DX to VST format change, vendors changing plug-in IDs, something else or some combination. In any event, the best way to future proof is always bounce tracks. Then at least the original and processed audio tracks are available, hopefully the future DAW will read the project format.

You are missing something. The plugins supplied with Sonar are not, with some exceptions, an integral part of Sonar, they are part of the marketing plan for the product. Most users are going to be choosing plugs that come with Sonar or from other developers on the basis of characteristics that they value in those particular plugs. There is no one-size-fits-all effect plugin, and the vast market for effect plugs exists because each plug has unique character. So if you substitute reverbA for reverbB automatically, you are doing the user a disservice. The point of having the ability to use a wide variety of plugs is that the user can choose. Freedom means work. 

In a nutshell if you buy a car radio and put it in your car, and the radio broke you wouldn't take your car back. After a while it's possible your car radio may stop working as expected (your favourite radio station moved from FM to DAB for instance). If that happened you wouldn't take your radio back to the manufacturers either. Besides after a period of time the warranty runs out.

Welcome to..... er..... life.....