I'm not sure I agree; apart from radios like the CR-1A and ELAD FDM-DUO, SDRs can be thought of as 'desktops' since they can't operate without a PC, which pretty much limits their portability (yes, it can be done, but it's pretty clumsy).
And let's face it; a good mid-level SDR will blow most portables right out of the water without breaking a meter band (heh)
Yes, SDRs have a big learning curve, but with that comes monitoring ability that desktops (the few that are still around) can't match. Mike