What do you propose MS/Asobo do instead? Test each simple addition and change to the sim against thousands of addons and tens of thousands of mods?
Then there would never be any progress to the sim.
There was and always will be change to any platform that is being improved upon. That’s the nature of progress.
If a new Windows version comes out and breaks Adobe Photoshop, I also would expect Adobe to fix it.
The sim is the basis and the addon developer has to adapt his product to keep it working. He’s the one charging money for it. Asobo/MS will give you 10-12 updates a year for free so I can expect free updates from the addon developers as well IF the sim breaks the addon.
After all the addon dev will be the one who can more easily find what’s wrong and fix it. And if a product gets abandoned it reflects badly on the dev’s commitment to his products.
And anyway: that doesn’t even happen very often. Most scenery addons and tools have bee working fine through all MSFS updates. The ones most affected are aircraft.
THIS addon we’re talking about also still works if installed manually. The seasonal layers have always been horrible for performance. That’s not new to SU10.