No, the dev tools comment was just a way to measure it's maturity. Once we see apps like Eclipse ported to Android, that's when you'll know Android is a serious contender for the desktop market. But I think that's a long ways away, as the OS is still geared toward single app/single screen. Not so much as Apple is, and that might soon change as I heard there's a commercial app out there designed to allow Android apps to run inside overlapping windows on Android tablets. So maybe by Android v5 (Jellybean)?
Well, fragmentation is a potential problem for Android, but that's a characteristic of open source projects - they often fragment because they can. The big worry was with Amazon as they seem to have a very focused requirement from Android, but so far it seems to all be one big happy family still. There are also a lot of custom Android builds but so far it seems the guys at Android have no problems gobbling up the good ideas since, hey, open source is a two way street after all. Will companies like Samsung decide to break off with their own version of Android locked to their own app store? Perhaps, but that could put them at a disadvantage as well. If you think about it, Google is likely to continue with it's current model even if some vendors go rogue. But those vendors will then have to not only fund all future development, but also deal with users who "jailbreak" their device and install a custom rom based on Google's open code. And to boot, they'd use their Google Android phone with a special app from the Google app store to jailbreak their rogue Samsung TV. I think Android's success is based on not being tied to any one vendor. I would think Vendors understand that and would not be quick to mess with that. We'll see.
One thing to note: Google phones can be "rooted", but that's mostly to gain lower level access. Some special apps do require that. Google does allow rooted phones on the market, but allows app developers to decide if their app can be installed on rooted phones. From what I gather, few developers see any value in filtering out rooted phones. One exception is the movie industry which still wants to encrypt their downloads and tie them to a specific account. Rooted phones can get around that and those with rooted phones may not be able to download movies from some sites. But that doesn't mean people don't wish to root their devices. ASUS has promised to release a special tool to root the back ordered Transformer Prime, but with a warning that they may not be able to rent movies online. I kinda like this approach, although ASUS says it will void your warranty as well which kinda sucks. But still, you have the option. Still, you have less reason to root an Android device than you do an iOS device as Android already allows you to install from any source and exposes your built-in SD card as a flash drive to a computer (meaning, you don't need specialized software to transfer data back and forth). But you're right, vendors may try to change all that. We'll have to wait and see.