Steam - The Digital Distribution Juggernaut

Steam today is near ubiquitous when it comes to discussing digital distribution of games (and now even software) online, both legally and illegally. Steam today has over 1860 games, 54 million (and counting) users and approximately 50-70% market share of the digital distribution market. It’s this fact I’d like to discuss today.
Although there are few criticisms that can be laid at Steam, the monopoly tat Steam has over the digital distribution market seems to be the most worrying. Simply, it seems as though no one is going to be able to catch up, meaning Steam (and Valve by extension) are just going to keep getting further and further ahead of every other attempt at a Digital Distributions service. Indeed, the only company that seems to be able to sort of keep up with Steam is the service Good Old Games, and that’s only because they primarily deal in older games, which isn’t really where Steam has its catalogue at.
The problem in the future that I can see coming out of this is that Steam will end up in a near unchallengeable position in the market, and will thus be able to charge whatever they want for their product. We’re already seeing this somewhat in regional pricing, which though it is set by the games companies themselves, it doesn’t seem to be something that Valve wishes to concern itself with, which is troubling to say the least.
This could all just be overreaction on my part, but I feel it bears keeping in mind as we go forward. There doesn’t really exist a regulatory body for online sales of digital games yet, and this more than anything I think is the most worrying thing. I don’t believe it will ever really be a problem in the future, but still believe it pays to think about it, just in case.