Multi-Use Paths always devolve the same way due to poor design. Not much has changed since the 1970s when I first encountered the MUP concept in parts of San Diego. Until very recently Fort Worth's Trinity Trails MUP was designed the same way: Mostly a standard suburban sidewalk, about 4' wide, thousands of squares of concrete arranged into meandering paths. Not wide enough to safely accommodate cyclists speeding by in opposite directions while weaving around joggers, pedestrians, kids and dogs on 50-yard-long retractable non-leash garrotes.
During the past year the MUP has been widened in some high traffic places. But it won't solve the inherent design flaw, or attitudes of users -- all of whom assume their usage trumps all other users.
My philosophy, as a cyclist, is to learn to live with the realities of MUP, slow down, and not holler "Onyerleft!" every few minutes, expecting everyone else to "Git outta mah way!" just because I'm on wheels. That's the same selfish attitude that makes streets unsafe for cyclists.
I've found plenty of reasonably safe places to ride, so I use the MUP only when absolutely necessary as part of a commuting route to and from downtown. Usually that's at night and off-peak hours, so there's rarely any conflict. If it's during peak hours, I expect to yield priority to pedestrians. I expect joggers to be wearing earbuds and deafened to my approach -- heck, I wear earbuds when I'm jogging, although I don't jog on the MUP. There are plenty of places in my neighborhood where I can jog safely while listening to music or podcasts.
As a cyclist I've observed how people use MUPs for years and IMnotsoHO, cyclists are the prime offenders to routine courtesy. A pedestrian meandering around the middle of a 4' wide path or jogger unexpectedly turning left into oncoming traffic isn't nearly as big a danger as my fellow cyclists blasting down the narrow path at 20 mph, head down and hands on the aero bars, or riding side-by-side with partners, expecting everyone else to get out of their way.
After years of watching that behavior, I understand why some dog owners leave their dogs on long leashes, especially the women walking with two or more dogs. They're fed up with being crowded by wheeled users on bicycles, skateboards, etc. The women are fed up with being harassed by men -- yeah, that's at least a weekly thing, per local police reports, and probably more frequent abuses that go unreported. They're using their dogs and leashes as boundary markers to give themselves some buffer against the nitwits.
Granted, that isn't most of us. Most cyclists I've seen aren't that selfish, aren't MUP bullies. But it takes only a handful to give us a bad reputation among other MUP users. I see the complaints on social media.
I walk and jog a lot in my neighborhood and get the same treatment from the non-cyclists on bikes. These aren't riders who self-identify as "cyclists." It's just transportation for them, after being de-horsed by DUIs, economic downturns, etc. Some of them are obviously mentally ill, shouting and cursing non-stop as they cruise around the neighborhood. There's zero expectation of common courtesy from them, so I keep my head on a swivel and eyes on stalks when I'm on the sidewalk in my own neighborhood. If these guys on bikes ever do use the streets, they're the salmon ninjas, the guys riding without lights at night on the wrong side of the road. Or weaving unexpectedly across six lanes of opposing traffic on the busy boulevard.
Complain if it makes you feel better. It won't change anything. People are people and every society develops its variation of the
Tragedy of the Commons. Sometimes people will demand "trail marshals" or some variation of traffic cops and hall monitors for the infrastructure shared by pedestrians and cyclists. But there's rarely, perhaps never, any widespread support or consensus on regulating recreational infrastructure the same way we do motor vehicle infrastructure.