A lot of what you say here is relevant, but I think it's missing some of the depth. I put responses in bold.
Anyways... all things said and done... Really There's benefits to all the different viable strategies: Control, Aggro, Midrange and Combo. At different points different strategies may be stronger than others. Right now Combo is fairly strong, and because of this Midrange is weak. When Midrange is strong, Aggro suffers. When Control is strong Combo tends to suffer. At the same time though, When combo is strong, Control will become the primary alternative, and when midrange is strong people will look to find combo's. When Aggro is strong people will look for Midrange. Because of this balance, you end up having the Rock-Paper-Scissors Magic play that we consider a healthy meta. Overall control becomes the preference of pro's because it has the most balanced results in a healthy metagame. This doesn't necessarily make it strongest, but most stable and reliable, which is equally important. It's a rare thing when control is bad. It takes some pretty specific things to happen to make control a poor choice.
Bolded the most relevant statement. Going into an unknown or even simply a diverse metagame, control is generally the best choice since it generally has a decent shot against any archetype.
Aggro is very often good. RDW, R/G beats, Rebels, Goblins/Bidding, Affinity, Boros, Kithkin/WW, Tempered Steel, Zoo, and plenty more that I'm sure I can't think of right now all fall into the "aggro" category and are all excellent decks in their own right. As a matter of fact, several of the aforementioned decks completely dominated formats. (Rebels, Goblin Bidding, Affinity, and Tempered Steel)
Bolded the most relevant statement. Going into an unknown or even simply a diverse metagame, control is generally the best choice since it generally has a decent shot against any archetype.