I think the studios have overplayed the popularity of the franchise. If you have one film every other year, then the the dedicated fans might go at predictable levels. The Force Awakens, Rogue One, The Last Jedi all coming hard upon the heals of the previous movie may have flooded the market. Add a lackluster film and you have a recipe for a big money loser.
I'll catch this one on a trans-Atlantic flight next year.
Solo failing has nothing to do with general 'Franchise Fatigue'. Marvel is about to release it 20th entry in the MCU in 10 years next month. The majority of people love those films and keep showing up.
Star Wars is a larger and more popular film franchise than the MCU. This whole backlash isn't even about Solo itself. It's about a large portion (30-40%) of the fanbase being extremely angry and frustrated with the way Kathleen Kennedy has quickly taken the series in a wrong direction by completely misunderstanding the entire appeal, tone, mythos/lore, and themes.
It's backlash against the HORRIBLE 'film' The Last Jedi and backlash against Rian Johnson getting his weasly little hands on any other Star Wars project much less a Trilogy of his own to interject his subversive perverted nihilism.
Kennedy is not making the films fans want to see..... she's injecting her own personal SJW Identity/Gender Politics into it to make it something SHE can identify with when the whole thing was already organically diverse and rich to begin with. The politics are so hamfisted and clumsily shoved in it takes you completely out of the experience.
George Lucas subtly wove history, mythical archetypes, and current events into Star Wars to make it just relatable enough yet still....in a Galaxy Far Away.
Now, A Galaxy Far away could never be closer because Kennedy is on the nose mirroring current sociopolitical events to uncomfortable levels when most people go to the movies for an ESCAPE from troubling realities.
She has torn down almost every Legacy character at the expense of an agenda and pushed other characters to the forefront without them being fully realized and developed. Raise your hand if you wanted to see Han REGRESS to being an Absentee Father and Husband....or if you wanted to see Luke REGRESS to being a murderous cowardly hermit who lives in fear devoid of any of the optimism woven within who he is as a character.
She teases Diversity but it's Diversity not done well with one-note characters with poor to absent arcs. I want to Love Finn but he's treated as a comedy relief joke. Even when he almost has a moment to shine it's undercut by another characters actions. How can I take him serious? Poe is an unbelievably stupid hot-head. Kylo is a temper tantrum throwing teenager who is anything but intimidating. Rey is grossly overpowered without having to earn any of her progress and pretty much makes no mistakes of consequence to learn because apparently she doesn't need to learn.
The whole thing is a hot mess of absolute garbage. It's a Trilogy with no connections of plot points or themes because each Director wrote the stories in an isolated vacuum instead of storyboarding the whole thing out into Three Competent Acts that complement each other as opposed to undercutting each other.
Long story short: It's not Star Wars franchise fatigue.... it's Mediocre/Poor Politically Driven Star Wars Film Fatigue.