Same here....I have also noticed decrease in quality.
I was trying to find some better grip but none of them made me switch(and I have tried them all). Just Supergrap comes close. It is hard to switch when you use the same grip for last 10 years. Recently, just for run, I have bought 3-pack of pink Wilson Pro Overgrips. And to my big surprise...they are the good old quality! Not like the new white ones I have.
5x PT630, 2x PT630 SE1, 14x i.prestige MP, Solinco Tour Bite 1.25