There's a few things that come to mind. Nokia is the single largest company in the market, it luckily does well in developing world markets too. Being the biggest ship I imagine it's harder to change course, so to speak - iPhone was a shock to the entire industry, especially Nokia - it is clear from Maemo 5 that their number one priority is services integration (by that I put an emphasis on web) as well as user experience (primarily UI design).

You are correct in being unable to identify Nokia's masterplan, I don't think they have one, the 'try and see' approach that you say seems accurate then. However they've been developing both Symbian and Maemo in parallel whilst all the while strengthening their position through strategic acquisitions (they own Navtek right?) as well as Qt, both of which are some of the most fundamental under-pinnings, or will be in the short term.

I also agree with you when you say that they could've added telephony in the N810 but instead I think they could've upped the integration in this device, although I won't know until I use it, it seems as if telephony is second fiddle. However that could be just in relative order to the good web experience you'll have on the device.

All I can say is that the N900 is a big boon for Nokia. Their marketing needs to be very in your face and focussing on these very visual features, just like the iPhone is doing. The possibility of operator partnerships also gives the device an almost infinite degree more visibility than just being a specialist device available from Nokia's own shop.