Think it's just what they are doing with MCU as well (after the getting the Fox properties) e.g. taking their foot off the gas. Common sense if u want to maintain dominance. Plus, Disney is getting good buzz from the planned MCU series and Mandalorian. They just don't want to take a wrong step. It's all about keeping the dollars rolling in and keeping the stock up. There's competition in the streaming arena too - Disney has invested a fortune, but so has the the juggernaut Amazon in the upcoming LOTR series.
And plenty will go see SW like they went to Captain Marvel (without knowing a thing about the MCU) 'coz of the release date - u can take families etc. to SW. Dunno if it's ever been *guessed* how much profit comes from "true fans" vs. folks like me, who aren't "true fans" or into the lore/backstories.
Some article I read pointed out that every single SW movie ever released had a bunch of backlash and complaints at release, tho don't know if it was anything like TLJ. Time changes the way people look at stuff. I'm sorry I listened re Solo, which actually I think is pretty enjoyable (when I finally saw it). Anyway, tickets for next-day matinee purchased. All the fan events completely sold out, and around me that's a LOT of theaters. SW will make first weekend numbers, no matter how pedestrian it may or may not be. Honestly the trailers haven't done much for me, and Rey seems to me to be too scrawny to be a badass, but whatever.