I'm sure they could buy the moon too, if it were for sale.
I appreciate you haven't experienced commerce for real, but it isn't as simple as that. For starters, VStep is a private limited company- not a PUBLIC limited company. So you can not very easily force a hostile takeover of a private company. Unless the owners of the said company wish to sell..
Now, if you had said "Micromush could make its own simulator and sell it at half the price of SS, until SS drops it, then MS puts its price up" you could have a point; MS could be classed as a predator. However, in the EU, GB and your own America, there are laws against that.
If you wish, I would be very happy to explain a bit more how these 'anti-trust' rules (using US terminology) actually work. However, I suspect you already know far more about it than I do