I recently talked to my kids about the American postal service and how you can still send things "general delivery." It's a little used option and you can't use it to replace a regular mailing address, but when I worked in insurance, I did send a check "general delivery" once. I think the family in question was living out of an RV and traveling around regularly. Maybe they were retired. I did not really know. They had me send the check to the nearest post office. These new fangled RV lifestyles would not work so well if you could not occasionally use this very old fashioned thing called general delivery.
While I was working in insurance, every time they upgraded, it introduced new bugs and some upgrades (where we would migrate something to a whole new system) failed to be backwards compatible. This created real problems. It was still necessary to preserve old information and old methods of doing things. For example, most of the claims were done on a computer using digitalized images of the paperwork which had been submitted. Once in a while, it was necessary to do an actual paper claim. Not everyone knew how to do a paper claim but it was information that had been preserved. I repeatedly ran into situations at work where things could potentially just go to hell in a hand basket if some old methodology were not somehow still preserved and available in spite of being outdated.
Someone, somewhere still uses these browsers for various reasons. I am glad someone sometimes works on this type of issue, never mind how silly might appear to folks who take it for granted that upgrading your system to the latest thing is the norm. It may be for you. It isn't for everyone.