Since the financial crisis, there's been a palatable and growing sense of discontent toward the so-called too-big-to-fail banks. The chairman of the Federal Reserve was grilled three weeks ago by senators after a study estimated that the nation's biggest banks get an implied government subsidy of $83 billion a year. And last week, the Attorney General was castigated by Senator Chuck Grassley for not pursuing the largest lenders criminally, referring to them as "too big to jail."

The irony in all of this is the fact that the big banks have grown considerably larger over the past few years. Wells Fargo (NYSE:WFC) has nearly tripled in size since the end of 2007 thanks to its purchase of Wachovia. JPMorgan Chase (NYSE:JPM) has grown by more than 50% over the same time period following its acquisitions of Bear Stearns and Washington Mutual. Even Bank of America's (NYSE:BAC) assets have increased by 29%. The only exception to this rule is Citigroup (NYSE:C), which has shed nearly 15% of its assets over the past five years.

While this may seem paradoxical, the reality is that, up until now, the financial crisis has served as an enormous catalyst for consolidation. Have banks failed since it erupted? Of course. Since the beginning of 2008, 472 have met their regulatory maker. But the vast majority of these consisted of smaller, community banks. As you can see in the interactive chart below, between 2005 and the end of last year, the share of assets held by $10-billion-plus banks has ratcheted up from 73% to more than 80%.

The Evolution of Too Big To Fail: Market Share by Bank Size | Infographics.

Beyond this paradox, the point I'm trying to make here is simple. While politicians -- even seemingly well-meaning ones like Senator Elizabeth Warren -- use the too-big-to-fail issue as a way to garner political points, breaking up the big banks goes against decades of history. On the heels of the deregulatory fervor of the 1980s, 90s, and 2000s -- which many still-serving politicians championed at the time -- a handful of financial institutions have effectively cornered the financial industry. As a result, the question now isn't whether big banks should be broken up, but rather whether it's even feasible to do so.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.