This is heavily correlated with your age (or, as you put it, "years in the business".) We old-timers clearly remember the days of Moore's Law, or more precisely, the days when Moore's Law had a direct impact on single-processor performance.
For me, every upgrade was at least a factor of two improvement to pretty much everything. It was a qualitative difference -- things that just didn't make sense to run were now reasonable to do, things that meant leaving it overnight could now be kicked off before going to lunch or whatever, things that required scheduling were now causes for slashdot breaks (age, remember?), and those minutes-long jobs were now something you could run and wait for without context switching.
I could go on for one more step -- except that's kind of where it ended, at least for reliable improvements. Stuff that was almost buttery smooth might become buttery smooth, but stuff that was buttery smooth already might start lagging some here and there.
These days upgrades are more about SSDs, RAM, decaying batteries that tip you over the edge, connectors, or maybe the collection of weird compatibility problems (eg 3 monitor support) that you've sort of worked around but the workarounds are breaking down, and you have this naive notion that the latest greatest laptop will magically be more robust. (Instead, you usually just trade over to a different set of problems.)
I'd agree that the SSD switch was the biggest boost in recent memory, and it's been about a decade since I've experienced one of those glorious upgrades of yore. And I miss them -- the heady excitement of everything being better is now replaced with a nervous inventory of everything I need to work or think might be improved, trying it all out in hopes of feeling some improvement or at least having it continue to work.