To roll 128 tick is simply a change from -tickrate 64 to -tickrate 128, dude. I know what I'm talking about. I've set up various game servers for many games including this one. It doesn't take a nasa supercomputer to run 128 tick. It also doesn't cost all this money you think it does.
They're a company who makes money off of Dota 2, and barely CS:GO. They would do it to considerably increase the the ability to play matchmaking and increase their player-base.
There is no investment when it's a simple change to the starting arguments of their servers without much server performance loss if any. Of which, isn't even the argument they used when they said no. They said NO because of low performing PCs of clients. This was stated years ago. It's 2019, it's time to stop caring for kids with potatoes as PCs.