It was an interview with Gabe (or maybe someone else seinor) when they first anounced the first Medic update. They asked if players would be able to buy the new weapons rather than have to unlock them and they said there was no plans to ever move to a microtransaction model and that they were fully committed to continued free updates.
I'll see if I can find it, but it its going back a number of years...
No plans. Plans change, however, and they have remained committed to continued free updates, so I don't see a problem.
Personally, I love where TF2 is right now. I still use some stock weapons on my characters, but I use lots of the unlocked weapons as well. I use the Your Eternal Reward dagger for my spy, along with the Cloak and Dagger watch. This gives me a massively different playstyle, making it far easier to take out sentry nests, while making it hard to initially start off due to the lack of disguise kit. There are pretty much no 'upgrade' weapons, only sidegrades that are situational. Sure, some people don't like change, but looking at the gameplay stats, and the fact that by your own admission all the servers that offered that are closing because nobody plays on them, it is clear that the game is still incredibly popular and the majority of the community supports the direction the game is taking.