Last I checked there were 15 or so devs still attached to maintaining TF2. And the servers would be split because bandwidth that would have been allocated entirely to OW2 will now share that space with OW1, you’re asking them to reserve space in their maintained server lineup for a game they no longer profit from when it can be devoted to others, they’re a business not a charity. And when new heroes/skins/maps are added to OW2, you can bet OW1 players would complain that they should easily be made compatible for OW1, meaning even more devs splitting their attention with balance changes and such.
You say “the community is abandoning Overwatch 2 because they want Overwatch”, sorry but unless you have actual real life polling data to back up that assertion you’re just talking out of your butt.