F2P before completely shutting down, maybe?
Eh, maybe, but IMO that has it's own set of issues. Making the game full F2P at this stage would likely topple the the marketplace-based economy, as there would be an influx of people hopping in for 10 minutes and then dumping whatever cards they get. Most of them would end up being just a cent or two. At that point you may as well give every player every card because it would probably cost less than a few bucks for a complete set; buying card packs would be a fools errand because it would be way more expensive then buying cards on the market. Then you've burned your early adopters too, some of whom may have dumped tens to even hundreds of dollars into the game for complete collections, so they would likely want to offer them some sort of concession too. It would be a very delicate dance to pull off, and I can't really wrap my head around how they would transition into that model and still actually make some semblance of money off the game, but maybe some big brains at Valve have it in their pocket. Idk.
And even then, it's probably not enough. The game isn't Uno; it's very niche and complicated and like 80% of people who jump in it as a F2P game are just going to say "it sucks" after they get crushed in their first match or two and move on to something else anyway.
i think the mobile version not being out yet is one of the biggest problems this game has at the moment though. I would actually play this game a lot more if I could pull it out on my commute or lunch break and play a match or two. As it stands now I'm never really in the mood to sit down and play a match at home, personally, when there's so many other things I could sit down and play. Being able to take the game on a bus or over to my friend's place to play them head-to-head with raise my enthusiasm level a bit. I'm kind of bewildered that the mobile version wasn't ready at or near launch, and we're now almost 3 months out without word of when it's coming.
It's all a bit of a bummer because I find the core game a lot of fun, but I'm also part of the problem because I don't play it too much; the reasons for that have basically nothing to do with the cost of cards or entry though.