Riot's PBE has to take on the demands of every server playing it since they only have one server available for it. And its a bigger game overall than Overwatch. That said, TFT should absolutely be linked to standard progression because of nonsense like this. If people want to test the changes they have to be active in LoL, TFT is considered irrelevant... yet how are people going to test TFT if they're primarily TFT players?
Like I forget how many games it took me to get Honor 3 but I wanna say its like 50-100 games. You have to play LoL regularly to generate the games and make sure to be polite during the process. I know if you get honored regularly it gets done quicker, but even when I was getting several honors a game it took ages.