I'm showing my age here, but I played Magic back in the mid-90s and know a bit about its history.

Oddly enough, the feature intended to self-limit what destroyed the game is one of the most deprecated, disliked features that is almost never used: the ante. (For those unfamiliar with M:tG, the original rules stipulated that each player wagered one random card from his deck and the winner got the loser's ante. There were also spells that could increase or alter the ante.) There's enough volatility in Magic (i.e. the person with the better deck might win 75% of the time, but not 100%) that it created real risk in loading up on expensive cards, because you might still lose in spite of them to a guy playing a deck full of powerful commons like Kird Apes and Lightning Bolts (both now OOP).

The problem with the ante is that you're likely to get a card that isn't very useful to you. If you're playing a weenie deck, and you get a 5/5 Shivan Dragon (in its heyday, a card that was $20 because 5+ power creatures were still hard to come by, except for green vanillas with high casting costs) then, while you got a "good" card, it's not congruent with your strategy.

I think what saved Magic was the fact that most kids who played it had fathers who were collectors (from the era of baseball cards). Except in places like Atherton where $500 per week was a typical 13-year-old's allowance, no one of Magic's target age could actually afford to play unless he got a parent or uncle or much older brother into collecting and could grab the dupes. (Because of the rarity tiers, getting a complete set of any expansion involves buying lots of cards and generates a ton of dupes.) It was kids playing with their collector fathers' and uncles' dupes that saved Magic.

Relative to other hobbies like golf, skiing, or scuba diving, Magic isn't astronomically expensive. A couple thousand bucks per year for your hobby or sport, when you're in your 30s, isn't a big deal. The cruelty of it is that it has adult prices but is marketed toward 13-year-olds.

In tournament play, you have to choose between "Type I", which has enormous upfront costs because it's dominated by super-powerful cards that've been OOP for almost 2 decades and cost $1000 a pop, and "Type II", which requires you to buy a new set of cards (to the tune of about $1000 for a competitive deck) every year, and limited/sealed-deck varieties which are fun in their own right, but take out most of the planning and deck construction (which is, IMO, most of the game). I remember in 1997 when people complained that it "cost almost $100" to have a decent deck. Now, you'd have a hard time playing with one under $750.

What's also slightly offensive is that the game is explicitly programmed to favor people who spend more money. In golf, expensive clubs deliver an advantage over cheap ones, but that's not by explicit design. It's just how the physical world works. Moreover, a good golfer with crappy clubs will still beat the pants off of a shitty golfer with the best clubs in the world. In Magic, there is a skill of deck construction that money can't buy, although the Internet has taken that away because one can play already-constructed decks, but if you have a good and expensive deck, you've basically been delivered enough power to win most of the time (but, again and to its credit, Magic has enough volatility that you won't always win).