As a former casual Magic player in the early 90s, I'm going to go ahead and argue that you just aren't familiar enough with games other than Magic that have come out either before or since. Just among customizable games MTG only ranks 14th on boardgamegeek. It's beaten out not only by games that don't require constant infusions of cash (notably Mage Wars at #2), but other collectible card games (Android: Netrunner at #1).
Throw in games that have fixed cards but can be played with a draft mechanism (e.g. Race for the Galaxy; Omen: A Reign of War -- both games that I own and can recommend highly) and you have even more choices that won't break your wallet.
There are over 50,000 board and card games in the boardgamegeek database. I assure you that there are plenty of them that many people find more fun than Magic, even among people who find deep abstract strategy games stressful.
Note that Magic is also far from the only modern board game to have both online play and tournament infrastructure. To take an atypical example, one of my favorite games, Dungeon Twister, (imagine the mutant hybrid child of Chess or Arimaa and Dungeons and Dragons) is both available for Playstation online, and has (or at least had) tournaments in both Europe and the United States.
TL;DR -- Your claim is informed by availability bias and insufficient sampling.
Does Netrunner have high-prestige tournaments and a World Championship? I know there are some games, such as League of Legends and Starcraft, that have ambitions of being "e-sports" with highly competitive, publicized gaming circuits. It's that kind of thing that I'm attracted to.
On ChrisHallquist's post extolling the virtues of money, the top comment is Eliezer pointing out the lack of concrete examples. Can anyone think of any? This is not just hypothetical: if I think your suggestion is good, I will try it (and report back on how it went)
I care about health, improving personal skills (particularly: programming, writing, people skills), gaining respect (particularly at work), and entertainment (these days: primarily books and computer games). If you think I should care about something else, feel free to suggest it.
I am early-twenties programmer living in San Francisco. In the interest of getting advice useful to more than one person, I'll omit further personal details.
Budget: $50/day
If your idea requires significant ongoing time commitment, that is a major negative.