Sorry about this being an absolutely worthless post!!
I was cleaning with squeegees from 1968 for the next twenty five years. Blades were all fine.
I recently tried some, they were very poor they kept "jumping" "sticking" they had lost their "smoothness".
I know we all think things years ago were better, perhaps yes, perhaps not.
It turns out that the blades I used were "real rubber" now they are synthetic.
I think that trad cleaners are having a hard time!!