From this point of view, I think Matthew is probably correct: if the thing you want to concentrate on is writing boring old "bread-and-butter" business applications, then a platform that builds on the existing "bread-and-butter" platform of C# in Visual Studio will be a more attractive proposition for businesses to get a footing on the tablet bandwagon. And even it if wasn't more attractive from a development perspective, "Microsoft Windows tablet" may just sound a bit more 'serious and businessy' on a tender bid.
But, I think Matthew could have included a few other important observations (which don't necessarily contradict his point of view and if anything support it-- but which are nonetheless worth mentioning):
- the iOS "ecosystem" may still present an attractive market to developers in the sense that Apple have done the job of (a) isolating the 100+ million people with sufficient income to splash out on fancy toy; (b) sold them that toy on the basis of it providing enjoyment: or in other words, persuaded them that it is to their benefit to spend money on this new gadget (and associated apps); and (c) built a system for developers to market fairly effortlessly to that income-to-spare-for-toys-and-apps sector;
- games (and, apparently, knocking out games that you can sell for a buck or two a download) remain the predominant iOS market; the iOS development framework allows you to write virtually all of your application in a bog-standard C/OpenGL paradigm which will allow the creation/porting of a huge number of games with a minimal learning curve;
- while slightly quirky, in a sense Objective-C is just "another C syntax-based language" and if you stick around in programming long enough, you generally end up learning a new C syntax-based language every 10 years or so; indeed, "Java" as it looks today, and certainly how it will look if currently discussed language features make it into Java 8, is almost a whole new language compared to how Java was when it first materialised back in 1735 (anyone remember when Java didn't have inner classes, let alone generics or closures?);
So, while I think Matthew is probably right that we could end up with an 80:20 split in one market versus a 20:80 split in the other, I don't know that that means that the "not-the-boring-bread-and-butter-database-application" market isn't viable.