While I agree with the rest of your post and have been a life long Nokia fan. I do not agree with the reasons you stated for Android's success. Free apps is definitely one of them, but the rest aren't. Considering the sheer amount of Android smartphones being sold around the world, I would guess that less than 5% of them root and install a custom ROM, and an even smaller percentage of them install CM7 since it's not available for all devices. Same thing goes for launcher replacement. Some people don't even change the layout on the original launcher! If I were to point out the reasons why Android has been successful, it would be the following:
1) Wide range of phones available (I don't have to buy a Samsung phone if I don't like the brand and still own an Android device)
2) Free apps
3) Cool factor (Everybody's getting an Android. It must be cool, I should get one too)
4) Price (You won't get a capacitive display phone for 6-7k with any other OS currently)
5) Modding capabilities (With an Android phone, you can change almost the entire look of the UI without even rooting it)
I totally agree with most people here wonder why Nokia ditched Symbian in favour of WP7. Belle looks amazing and Symbian gave Nokia its own identity. With WP7, it will be just another fish in the sea of WP7 manufacturers. And the whole UI is not everybody's cup of tea. Some will love it, others will hate it for the inability to change anything about the UI. Not hating on WP7, but I don't find it very appealing. Yes, it is ultra smooth with zero lag and does most things a person needs from a smartphone, but if I needed those features, I'd rather go for an iPhone.