The thing is, MS does have decent ecosystem, and working hard to improve it further.
Outlook.com, SkyDrive, Xbox Music and games. Skype is already part of their ecosystem and integrates nicely with Win 8. I'm expecting that their dealing with B&N will provide them with good book store shortly. Movies and TV, not sure if XBox Live is already offering some (and how good the offer is), but looking at direction they are taking with new Xbox One (as in strong integration with cable TV), I'm expecting some steps forward there as well.
I don't think it is time yet to discuss of WP8 success or demise. WP8 is still less than a year old. Looking at first year or two of iPhone and Android sales figures, I don't think that WP8 in general, and Nokia in particular, are doing bad. I would expect them to go over 10 million devices per quarter by the end of the year, and while this is still a far cry from numbers Apple and Samsung are moving, it is not rounding error category any more.
In addition. WP8/Nokia seems to be good platform, both OS and hardware wise. WP8 won 2013 PC Mag readers' choice (http://www.pcmag.com/article2/0,2817,2416521,00.asp) and one of Lumias was Endgadget readers choice for 2012 (http://www.engadget.com/2013/02/20/winners-2012-engadget-awards-readers-choice/). Granted you will find polls where iPhone (or even an odd Android) are voted best, but customers' satisfaction is in general very high across the board... I also think Nokia is doing good job staying in the spotlight - releasing new versions of phones frequently (even if some of them are repacks), releasing exotic options (new PureView) and also covering whole spectrum of prices with colourful, recognisable devices.
In short, I think they are here to stay. Momentum is there, focus is there. Nokia is doing good job on handsets side and I think MS will also not disappoint with WP8.1 update. We will see more features on consumer side, better integration in corporate environment, and continuing growth in apps offerings.
I don't have crystal ball handy and can't read future from foam formation on surface of Turkish coffee mug (like some other folks around here believe they can), but I do think Nokia/WP8 are out of troubled waters, and have period of good growth before them. Don't know if they will ever reach iOS and Android, but I expect they will be profitable and sustainable.