The issue is simple, why pay 14 times as much for a card that is marginally better? Some cards don't even gain any stats as they level, why?

Higher level cards should feel OP compared to lower level. Currently level 1 cards are almost as good as level 3 cards, some are actually BETTER in certain rulesets.

Buffing higher level cards or nerfing lower levels would be the conventional fix. Every new addition brought in with this fundamental flaw makes the situation worse.

To me this is a work around for the much bigger issue that leveling cards doesn't give you as much game play advantage as it should.