It's the idiots who aren't switching over to segwit's fault. If segwit was already implemented then there would be so many less full blocks. Better yet just increase block sizes to some huge amount that increases automatically when the average block is 80% full.
You are definitely correct, SegWit helps to increase the block to the suitable size, but only 20% miners agree with it, the left miners are so selfish, if btc tx is so slow, users won't use it at all, miners will cry, they are too naive to refuse SegWit.