Why is it that the SOny Phones always lose some features on a higher model

I am a Sony Ericsson Phone buff. Never owned any other mobile because of the brilliant sound, amazing looks, user-compatibility and the fact that they provide the best features in the comparable range of phones among all brands.
Currently though, I am facing a dilemma. I have changed 3 sets over the last year (all Sony of course). When I changed from a K750i (a very old set, probably out of circulation by now)to a W350i, I was impressed with the sleek design, old-style flip and easy user-interface but it lacked an essential feature- No video recording, although it had a good video playback. Again when I lost the cell about a month back, I moved on to the motion-gaming phone, F-305. Amazing looks, better games but imagine my horror when I realized it would not back up contacts from the memory stick and vice versa. I had to spend hours filling the contacts manually.
Why is it that the higher end phones lose simple features which make life harder?