MLB draft vs. International free agent market

The recent singing of Aroldis Chapman for $30.25 million has got me thinking. The number one pick in this year's draft, Stephen Strasburg, is almost universally regarding as a better pitching prospect yet he signed for "only" $15.1 million. I say "only" because this was a record amount of guaranteed money for a draft pick. Still, why is it that the better pitcher in Strasburg received half as much money as Chapman?

The problem with this current system is that the International free agents hold a significant amount of bargaining power, where as the draft picks are subject to the team's will and the MLB's slotting system. The international players are free to negotiate with any team they wish which causes bidding wars thus driving up contract values. Chapman took up residence outside of the U.S. upon defecting Cuba just so he would not be subjected to the MLB draft and it appears this was a wise move on his part.

My question is at what point will we see American players leave the country and play in foreign leagues so they will be able to skip the draft and become free agents. We have already begun to see this is high school basketball where players have chosen to skip college and play overseas for a season or two before coming back to play in the NBA. Obviously, the competition levels, degree of difficulty and other factors are much different in baseball but for a supreme talent like Strasburg or an up and coming phenom like Bryce Harper, this could possibly be a lucrative avenue to pursue.

I am not suggesting this is feasible or even a good idea but it just goes to show the vast inequalities that exist between the two markets.