Usually valve releases boxes with skins for summer, halloween and winter. I dont know if some are made by valve or all are community created with a cut for the creators. But it seems a low effort way to keep making money out of an old game.
And TF2 is still extremely popular, both with high player numbers, active content creators, community tournaments and the like.
“Mergers” end up being acquisitions in the majority of cases. One company culture will prevail, one companies middle management will take over the administrative sides and depending on the structure also the technical side.