I don’t think anyone is playing how they play because streamers. Like DMs take ideas from them, I know I’ve stolen ideas from Matt Mercer, Brennan Lee Mulligan, Aabria Iyengar, Mark Humes, Brian Murphy, Griffin McElroy, Jerry Holkins in his guise as Jerriford K Horkrims, DM of Teh C Teams, and Victoria from Broadswords, and certainly at least a few others. But nothing I’ve seen suggests that any of these shows have anything at all to do with groups not doing long adventuring days. This was a thing before the rise of streaming, and it is now dominant because anyone who isn’t playing with the baggage of old school D&D is vastly less inclined to see 6 battles in a day as reasonable.