TomTom and your own kernel

I've started to merge the TomTom specific patches into a plain 2.4.27 kernel. Most of it is quite straight forward, since apparently they backported half of the kernel to 2.4.18-rmk6 (which is what they use as base). I don't really get it why companies still develop new products for 2.4.x, especially for really old version like 2.4.18. In the windows world, nobody still writes windows 3.11 applications, why do they start this kind of crap with Linux? *sigh*

Anyway, I'm thinking about a 2.6.x kernel port at some point, but obviously this is not an important issue on my agenda and I'd rather get some netfilter stuff running first.