Over on
KVR, the developer came on to say that he acknowledges the CPU-usage problem and will be doing some optimizations.
Regarding newer plugins being CPU-intensive: that's more an indication of the maturity of the product than about assumptions developers are making about what hardware we're using.
A developer's first goal is a functioning product that meets design specifications without showstoppers. His second goal is stability, stamping out the annoying but nonfatal bugs. Then he turns to filling out functionality that didn't make the cut for the initial release, like a button or knob that had to be hidden at the last minute because it wasn't fully functional yet.
Way down the list of priorities, the last thing you do, months or even years after the product has been released, is to optimize the code for efficiency. When you buy a version 1.0.0 of anything, you're not getting the polished version, you're getting the first version that didn't crash.
Pro-Q has been around since 2009, but even it saw significant optimization mods earlier this year.