Initial box office grosses are only 1/2 the reason Star Wars films exist, though. The other half, and the half the keeps on giving, is merchandising.
No one bought merchandise from TLJ, so much so, they made very little period for RoS. And then what little was there disappeared.
The Star Wars collecting market overall is stronger than ever, new products coming out all the time, highly successful toy lines, highly successful high-end collector lines, etc. - and it's all original trilogy, then Mando-verse/Baby Yoda, and then Clone Wars (not specifically prequel film, but that era).
Every company that makes these products has moved on, and did so long ago - if you look at all the releases that have come out for the past few years, what's coming out now, and what's been announced - it's like the Sequel Trilogy never even existed once RoS was out of the theaters.