Great article from Mr Spencer Fry and one with which I greatly agree.
The only proviso being that I’ve helped build a very successful business (WooThemes) on another platform (WordPress being the primary one), so I won’t be hypocritical.
I’m less concerned about the risks involved with the platform changing things, but I do agree that this is a frustrating relationship as you are never fully in control. But building on a platform also means you already have an established target market.
So I guess you need to pick your battles, right?