Well, some of us 'vocal' people (and I only recall two of us being vocal on the subject) don't go around saying Amiga software is great. Well, Fred does, but he also says when it's shit or better on another platform. I rarely comment on the good and bad of Amiga games. I do, however, criticize most things PC (always have, always will...) That's who and what I am and this is an Amiga forum, not an abandonware forum, so expect the obvious slant of views that appear in this neck of the woods! No need to get cranky about it!
You talk about incompatibility of A500 games on your A3000/030...well, I had to deal with that as well when I ditched my A500 for an A2000/030. It pissed me off, too. Most of those games were written in assembly and were not OS compliant. Since instructions tend to change with upgrades to the processor, it's to be expected. Yes, CBM made programmers aware of upcoming changes. And there were unused areas they were told would be implemented in the future and using these beforehand would probably break the software in the future. Why did they ignore these rules? Mainly because the programmers were not registered as part of CBM's development core.
It's been years, so I forgot the name of that division, but you paid x amount of money to obtain kits for developing software on the Amiga. I was sent the brochures about it and the info on their conferences and such (my business partner and I were, at the time, considering developing CD software at the time...we decided it was out of our budget).
You have to remember that during this time, there was a lot of development still being done independently and sold to software houses. Rarely did these people have the dev kits. Even most of the software houses were too cheap to buy them, so they were ignorant to a lot of upcoming ROM revisions.
Another element is the mere fact that software houses were fairly certain that their biggest market (the kids with A500's) would have machines that would play the games. They couldn't have cared less about the odd Video Toaster user who purchased a game for his souped-up Amiga. Frankly, the software industry still has a version of this mindset even today, despite your flowery summary. Where it differed then was that programmers coded to a specific machine's specs primarily (the A500) and used every tweak they could to squeeze performace from that box. That meant a lot of illegal instructions and rule-breaking (as far as proper code goes). Bad programming practices yes, but not neccesarily 'awful programming'. After all, some of the most innovative games of our time could fall under 'awful programming' using your analysis.
I can't agree that "some bloat is needed in order for games to run on different configurations", as you say. For example, when Codetapper fixes so many games to be hard-driveable and patches flaky code, it doesn't add any bloat at all to those games. And those games are not locked into the hardware configuration after he fixes them. Most of those games are hardware banging, OS-ditching, yet they could have been made to work if everything were in a tidy little box then (all developers knowing the rules, following them, making considerations for future systems, etc.) I still contend that bloat is not a requirement except, perhaps, on the PC.
And I realize how many things the modern PC has support for. They have nothing to do with a game, though, really, unless they happen to be used in the game (like serial linking, etc.) Why should all of those things that have nothing to do with a game have to bog a game down? I still find PC games jerky, personally. And when you consider how much horsepower and RAM there is, that's pathetic.