Indeed, it doesn't make sense for anyone to unlock their cards even if they were financially able to. A max set of Soulbound Reward cards which has 43 cards in it would cost 1438$ while a max Chaos Legion set of 103 cards costs under 600$.
Cards need to be burned so things get evened out. Otherwise, new cards will never ever keep their value as players are much better off botting with the cheapest cards in Wild once the new cards get dumped in there.