>Requiring me to spend money on new hardware in order to avoid a regression in my experience is somehow doing me a favour? Really?
No, of course not. If you phrase it like that, that is, ignore the point of removing it entirely and all of the benefits that come with it, of course it's not beneficial.
However, 96 DPI was never ideal. HiDPI won't just avoid a regression, it'll improve your experience, period. And with this new software change, you'll get a performance improvement, from better caching and easier GPU acceleration, and software engineers can delete thousands of lines of potentially buggy code made to work around the interaction of subpixel rendering with other graphics code.
Like, subpixel rendering is easy to understand in theory and that might delude one into thinking that it's just a minor annoyance, but it's an annoyance that permeates the stack. You have to special case the entire stack wherever text is concerned. Effectively, the text is being rendered at 3x the horizontal resolution of everything else. This brings in complication across the board. An example is that you pretty much have to do the alpha blending in software, and when you do it requires knowledge of the final composition. Doing alpha blending in software sounds easy... But it's only easy if you do it wrong. Dealing with gamma for example. Which makes life worse because you already have to do this for the other part of your graphics library, probably with a case for both GPU acceleration and software.
Basically, you'd have to render the whole screen at 3x horizontal resolution to remove the need for all of these compositing hacks. Nobody does this because subpixel AA was a hack from the get go.
In an era where battery life and TDP are actually important, finite resources, we want to remove these hacks.
P.S.: if you've never tried rendering large amounts of text on screen before, I highly recommend you try writing a piece of software that needs to do this. A few years ago I struggled to get 60fps rendering text for an IRC client, and of course caching the glyphs was horrendously complex thanks to subpixel AA. It would've been easy if I could've just used GPU compositing like all other graphics, but instead I resorted to hacks everywhere. Maybe today's computers don't need the hacks, but it's worth noting that yes, rendering fonts is resource intensive - you're just living on top of decades of optimizations and hacks to make it look like it's easy.