The problem is that you are comparing Hearthstone to regular $50 video games. It's more of a digital hobby than it is a traditional video game.

This kind of hand-waving just upsets me. Hearthstone is a video game, not some re-definition of a "costs-hundreds" hobby. It's modelled after a card game, but at the end of the day, all of its content is 100% digital.

It's a collectible card game

"Collectible" in the sense of "have to either overpay insanely" (via dust) or "hope I get the cards randomly" (packs). I know that the free to play model is popular and makes tons of money. I know that Blizzard loves that, and I would too. But it does impact the state of the game when subtle paywalls are erected like that (under the guise of "it's free to play").

This is the sort of mentality that makes these free to play engines their whales of money.

If you're giving out complete collections for a flat fee or making it too easy to acquire cards, then you've just killed half the game.

I'd like to see data on the number of users that prefer having to grind/earn every card they want, instead of playing the game that they want. To use another game as an analogy, Zelda offers many secrets and extras you can collect. Heart pieces is a good example. The point being that it doesn't affect the actual gameplay. Collectathon games can be fun, but not if you can only play a gimped version of the game before getting the gooides.

Also, if collecting is half the game, then the non-collection aspect of Hearthstone is also only half the game? The game itself?

Players have reached legend with f2p decks before.

It's possible, but not for the "casual" crowd. Especially if you don't take the Trump route and dust every single card you get except for the one deck you're gunning for.