I suspect other phone manufacturers will be less eager to invest in Android as a platform. Symbian's ownership was a huge problem back in the day. We will see a repeat of the drama I am afraid.
In my vision, these companies (Samsung, HTC, LG, etc) did not "invested" in Android. They used free Google software to actually save their own skins. What chance any of them would have in the smartphone transition using their own home-made software? I dont think they have much options now, the Windows Phone choice is not giving good results for Nokia and I think the only choice they have to compete against Apple is to have an unified environment so the users can benefit of more apps, and this is exactly what Android gives to them, for free.
"the Windows Phone choice is not giving good results for Nokia"
Nokia's problems have nothing to do with Windows Phone. They're still offering lots of Symbian handsets [http://www.nokia.com/us-en/products/products/] to compete head to head with iOS, Android, and WP7. A renaissance for the brick format or Symbian was no more likely a year ago than it is today.
For me, it's hard to see how betting on a MeeGo app ecosystem would have given them a growing market share over the long term.
Android rose because it was cheap and available as an alternative to iOS. Google realized a first mover advantage in the "not Apple" segment of the market. Now with Motorola Mobility purchase, they have the opportunity to bring more of the profits back in house.
I suspect that Google's long term hardware strategy, if they have one, is to go head to head with Nokia in the developing world by deploying the next generation of feature phones and collecting data in rapidly developing markets like Africa.
If Android, then Nokia would be in the same boat as HTC, Samsung, etc. are today...paying Microsoft to use Android and facing the prospect of going head to head with Google's house brand.
Note how Motorola and Sony do not pay Microsoft for using Android.
All the other Android vendors license Windows for some other area of their business. These two do not and Microsoft has no leverage to force them. (Yes, I know about Microsoft suing Motorola and Motorola suing Microsoft back).
Android benefits from the lock-in effect of Google Play and the apps distributed by Google, like GMail and Google Maps. It also benefits from all the improvements that Google is pushing at a fast pace.
Amazon may have the strength to open its own app store for the Kindle. But it can only do so because the Kindle is just a means to a purpose, which is consuming stuff from Amazon's store.
Apple may have the strength to build their own alternative to Google Maps, but they are Apple.
On the other hand, did anybody here ever used the Samsung App Store? (http://www.samsungapps.com). I didn't think so. And what's an Android phone without Google's apps and Google's Play? It's just a shitty smartphone.
Actually I think it's great news that Google buys Motorola, because maybe, just maybe, these phone manufacturers will drop those silly enhancements and start getting in line with the official updates.
Samsung at least seems to have far too much invested in Android now to consider dropping it (hell, they're making the best-selling android phones on the market).
This isn't a surprise for anyone, though. They have been working towards this purchase for a while, so if any of the manufacturers were likely to baulk at it, they already would have done so.
Here's hoping that google puts out some great handsets, and makes this a real game-changing move.
Samsung have always hedged their bets with OS's. Even while making the Galaxy S and SII they also made phones using their own OS (bada) and Symbian OS. They are currently producing a Windows phone (Samsung Focus S) in addition to Bada and Android devices. They are also involved with Tizen.
This is purely for their own phones too, not mentioning the parts they produce which go into others (original iphone processor etc.)
Samsung is however also investing in Tizen. So while I doubt they have any plans of dropping Android, I wouldn't be surprised if they have people working on plans on to handle a situation where doing so becomes expedient.
I had the impression that Samsung was readying themselves for this with Bada. There will probably give more weight to it from now on, while investing less and less in Android. It won't be an overnight withdrawal for sure.
Google doesn't have to treat Motorola specially. I think what Motorola gives Google is guaranteed buyin by at least one manufacturer to any of Android's initiatives. Think about the failure of last year's Android Update Alliance. I'm sure all the manufacturers were playing chicken to see if any other would actually invest the resources to keep their phones up to date. From now on when Android announces something similar, you can pretty much guarantee that Motorola is "willing" participant #1. I assume that changes the calculus of to what extent other manufacturers participate.
Mostly I think Google's gunning for the carriers at this point. Carriers seem to keep enjoying getting in Google's way.