For me, this thread is a great reminder that everyone's needs & uses are different!
I have no use for a 50cc saw. I tried one once, I owned a MS260C. It could do marginally more than a 35cc saw, but not much in my work circumstances. But, I don't cut firewood. I'm guessing that others feel much the same about a 35cc saw, to them, its probably OK, but they can do everything they need to with their 50cc saw?
At work my needs are >95% 35cc saw. The remaining <5% of my time I use a 78cc saw, a 23cc saw, or a 92cc saw (I could get by without the 23cc & 92cc saws too really!)
I even tried a 357xp once - good saw, but no need for it doing what I do.