Perhaps they fear it is going to cannibalize their S60 handsets (N97 et all), and Symbian is way more entrenched in Nokia than Maemo is.

Something similar happened back in the day in the PC industry. IBM delayed the launch of a PC with the 386 processor, to avoid cannibalizing the sales of their smallest mainframes which had a similar performance.

The result? Compaq launched the 386 PC before IBM. Ouch.

I don't want to think that for them Maemo is just a bandaid until Symbian^4 arrives...