Honestly, I think if several people came up with a document that showed the dev team how fostering the TF2 competitive scene would be profitable for them, then I think it would become their primary focus. Until that point, it will always take a back seat to things like new skins and hats, because Valve is a business, and at the end of they day, their primary motivation is money.
As for what we can do, I think the most important thing would be to grow the scene by attempting to get more coverage and exposure. Has anyone tried getting in touch with games journalism sites, e-sports broadcasting groups/streams/sites, or anything like that? Hell, when's the last time anyone saw competitive tf2 mentioned outside of a small side reference in an article about overwatch?
In order for the comp scene to succeed, it needs support from Valve; in order to get support from Valve, it needs to be profitable for them to do so, and in order for it to be profitable, comp tf2 needs to reach the wider audience interested in competitive gaming.
As a side note, I think the upcoming tf2 comp movie is going to be a great step in that direction. Show that and the i46 Fragumentary to an audience outside of the circlejerk of comp players and tf2 players who actively dislike 6's, and that could bring in a lot of people.