What you say is true from a historical standpoint. However, the notion above assumes that the studios continue releasing in 2008 at the same rate they have previously. I think 2008 has been pegged as the year where the studios want to make significant headway in establishing HDM.
I believe Fox has stated they intend to release 100 titles, which would be way more than they have done previously. Disney's first 1/2 08 leaked slate looks to be be fairly aggressive as well. I know these are "promises", and things could change. However, I think it's safe to assume that they'll get to 80% of what they promise much like Universal promised 100 titles for HD DVD and released something like 82 titles. (I apologize a lot of this is from memory).
Bottom line, I think it's safe to assume...
80-100 titles from:
Sony Pictures (on Blu)
20th Century Fox (on Blu)
Disney Home Video (on Blu)
Universal (on HD DVD)
Warner Bros (currently on both, though BD may get a 1/2 dozen more than HD DVD in the calendar year in the form of the 'missing titles' like Batman Begins, The Matrix, etc)
Paramount has promised 30-40 titles (on HD DVD)
I don't know about Lion's Gate and how extensive their catalog is, but maybe 20-30 titles from them on Blu?
Then of course, there's a bunch of smaller studios and independents.
Anyway, those are just rough estimates, some based on studio comments and obviously subject to change (and Fox has proven they can go AWOL at any time
).
In the end, the point is that if the studios are really going to grow HDM, I think previous release patterns are not necessarily indicative of future plans.
I fully expect to buy 50% more than I did in 2007 (assuming the BDA doesn't screw the pooch and let WB go HD DVD in which case that's a vote of 'no confidence' in HDM, and I'd be done with it).