The monthly subscription cost is about twice what it costs to pay USD 200 on each 18 month upgrade cycle.
Actually, they announced new aggressive upgrade pricing to the CC versions of apps which brings the price down-assuming you go with a longer term license.
Special pricing for existing customers
CS3 and later get Complete for $29.99
CS6 customers get Complete for $19.99
CS3 and later get Single App for $9.99
All offers require annual commitment
As far as the economics of the CC for Adobe, actually, it's been the success of the whole subscription model (and the technical difficulty in doing dual application versioning for subscription & perpetual licenses) that have driven Adobe toward doing this. Yes, it will alienate some users who reject the whole "cloud" thingie...which I understand (assuming the rejection is made based on real facts and not FUD).
As a book author, my life just way more complicated because I can't write for a fixed target with a known lifecycle...now it's a moving target that will be tough to do for paper based publishing (easier and perhaps better done with ebooks).
I'm also kinda melancholy about the whole change to the old model...as a long term alpha/beta tester, I always looked forward to a new dev cycle and seeing what the engineers came up with (and hammered on them to fix stuff). But this new model allows a freedom and flexibility that will, I think, lead to more rapid advances with new features on a more regular basis. But I'll miss the old way...
Edited to add the special offers...