"Impossible"? Likely never. The real question is if/when hobby developers will ever lose interest in doing so.
As more & more businesses & websites completely block devices using Win7 or an older browser version then it will become obvious that continuing to try to use Win7 &/or the older browser has come to an end. May be different for everyone. Some are still using XP & even older M$ versions on older machines but not to access the internet. Rule is: we go till we can't. End is a bit different for everyone depending on their individual computing needs. Me? Mine is a survival tool. I use it on 2 platforms for investing. I use it for VA healthcare communications. For all other government business like tax filing & SSA. 90% of my food needs are ordered/delivered via this laptop. All my bills are paid via this laptop. I have ZorinOS & a modern private browser ready to go the very minute my access is compromised. I think modern access security requirements will be what drives me away from Win7/FF. Live photos, finger prints, eye scans & 2FA keys are becoming more accepted & common. HD+ cameras & devices better supported with more modern software. You just have to let your own individual needs & requirements dictate "when" it is time to cut the cord. My 73rd birthday today. Making the rounds, checking for news or updates & keeping my account alive. Watching a couple other forums here as well. Still chugging along with my Win7 laptop, my MSE continues to be updated & works fine. FF 115 updated still working on sites with the help of my VPN in some cases. My secondary ZorinOS is primed & ready to go. Weather is fair, oceans are calm & smooth sailing ahead for now. Pray the same for all who are left here.