The following post contains a discussion relating to the competitive M:TG standard format. For the vast majority of readers it will consequently be of no interest, so if you are among them, please don't waste your time.
I was at a Magic tournament the other day, scouting the remaining matches after I'd finished mine, when I noticed a guy I've worked with next to me. He was waiting on a pizza order to feed the family when he'd seen me standing inside. He'd played before he had his two little ones, but the game seems like too much of a time and money investment for him to get back into now.
The standard format is undoubtedly a cash cow for Wizards of the Coast--other trading cards (sports or otherwise) simply cannot compare. Jace, the Mind Sculptor--which just debuted in Worldwake in February of this year--will now set you back $80 per (as a longtime control player, I saw this coming and consequently bought two playsets when he was going for $30). For every Jace, though, there are several junk cards like Near-Death Experience. With sets rotating in every few months, and core sets now being released annually instead of every two years, the need for players to keep their libraries up to snuff is a perpetual one.
Rapid increases in price like that experienced with Jace do more to directly benefit the shops selling the cards than they do to benefit Wizards' itself. Of course, the resulting increase in Worldwake pack sales does translate into more money in Wizards' coffers, but presumably at the expense of other sets, since the competitive environment is a zero-sum game (the utility of a card is relative to others in the format, not in an absolute sense).
The four designations of commonality factor into market pricing, of course. A booster runs 11 commons, 3 uncommons, and a rare, which, 12.5% of the time will turn out to be mythic. Cards are not valued exclusively on their in-game merits; they also double as collector items, and the rare stuff is more difficult to collect. But the list of dollar rares (as they're dismissively called) is long, while top uncommons fetch close to double-digit prices.
Using data from decklists entered in sanctioned tournaments from M11's release to August 13, 2010, I correlated mid-range card prices with their respective rankings among the top 100 most-used cards. The correlation is .27 (p=.01). It's statistically significant, but modest, which is what regular players would expect to be the case. The single most played card in standard at the moment is Lightning Bolt, a common which anyone who has ever played Magic at any point in time will recognize as the marquee red card, if not game's marquee card, period.
The reason people complain about the high cost of certain overly powerful rares like Jace is that he has too much general utility to be left out of anything that plays more than a splash of blue. To a lesser extent the same can be said for white with Baneslayer Angel and for green with both Vengevine and Primeval Titan (red is reliably the pauper's best option for being maximally competitive; black is also currently cheap because it sucks). If you're playing these colors but lack the respective cards, it's virtually impossible to compensate with something cheaper. Again, Jace epitomizes this--without him, blue collapses as a foundational color. So even though 90% of a competitive deck is easily acquired on the cheap, the few expensive rares propel top-tier decks into the $500 range.