$100 billion in assets by December 2010? In a best-case scenario for Schwab, they’ll be closer to $10 billion.

More realistic would be something like $5 billion. But let’s put the over/under at $10 billion by 12/31/2009 and put something interesting on the line, shall we?

Seriously. One-hundred billion would make Schwab the third-largest ETF provider in the world at current levels, surging past ProShares, PowerShares and Vanguard and nipping at the heels of State Street Global Investors. Having a built-in distribution system is a good thing, but it isn’t THAT much of a good thing.

And I’ll say this: They better get busy if they’re even going to reach $10 billion. We’re one week into the project and they’re sitting on a combined $17 million spread among four products.

Obviously, one week is not a legitimate test. My point is that Schwab moving into ETFs isn’t like flipping a switch. The bigger impact will be felt as they educate a broader audience of retail investors and financial advisers on the virtues of ETFs in general. That will take time. Eventually, those investors will start to dip their toes into the water with SCHB, maybe build assets in that over time and then branch out as well into a broader pool of ETFs. That’s why I think Schwab will help significantly grow the ETF industry, even above and beyond whatever assets they attract themselves.

I do think Schwab could eventually be a major player in the ETF industry. But it’s not going to happen overnight, and it’s not going to happen to the tune of $100 billion in a year, either.