Its nothing to do with Nokia the release , its Microsoft that's delaying it as windows 8 will be released next month.
err I wouldn't worry about Nokia surviving medi tend to blow things out of the water , Nokia still sell over 1,000,0000 phones a day , nokia deal a lot with developing countries and sell a lot of the cheaper handsets to them.
Microsoft has promised at least 18 months of updates
Windows 8 is what the intergration is all about ....
All new windows 8 handsets will run windows 8 and all the handsets will be updated at same time , so previous windows 7.5 phones will have 7.8 update , but all windows 8 phones will run same windows 8 version .
Nokia has continued to improve the lumia 800 etc so yes they seem to be a good company to keep users happy, they were constrained a lot with windows 7.5 hardware support limitations .
Its Microsoft so yeah they will have a lot of developers on board