I've seen some complaints regarding unobtainable trophies before, so you're not the only one, but I think most people are just over trophies/ achievements in general these days.
Back when trophies first started they were for completing interesting challenges that were fun to do like beating a game without being detected by any enemies. Now most trophies tend to be boring and time consuming like eliminate 10,000 of this one enemy or complete 100 races in multiplayer so I think most people just don't really pay attention to them anymore.
As for the servers still being online, well it's mostly a sunk cost thing. The servers are there and have already been paid for so the cost to keep them running is minimal and in the era of #stopkillinggames there's likely to be bad PR if when you start shutting things down. Weekly challenges on the other hand actually require the dev team to be putting in updates which costs time and money that could be used elsewhere.