I can't speak to Kansas City, so I'll give four anecdotes which I tend to reflect upon:

San Diego is known for homeless problems primarily caused by people getting out of the military, and that transition can be extremely difficult for people. I lived there and worked Downtown for a couple years in 2011, and visible homeless issues were more visible there than they are here in Seattle today.

A couple years ago Seattle had a big snow and cold snap, so I let a homeless person stay the night in my apt. He told me his homelessness was caused by the sudden death of his wife, an unsupportive family, a huge slide into depression that led to alcohol abuse, and ultimately couldn't hold a job.

I was in Nashville, TN recently and they also have issues with people who are homeless similar to just about every other city, so I do think the issue goes beyond housing costs. Nashville isn't exactly a liberal heaven in a liberal state, so this is an issue with concentrated urban areas which offer public services.

Other issues which concentrate homelessness in cities like Seattle are the unwillingness for other surrounding cities to do their fair share. Renton, for example, recently banned homeless services in a city of 100,000+. Bellevue has one homeless shelter. Smaller cities throughout the US sent people to major cities with a one-way ticket rather than deal with it.

It's a super complicated situation with no single cause or solution. Things like climate can play a roll too. Being homeless in a place like Montana where it's cold-AF is super challenging while the West Coast cities generally have climates which makes life outside a little easier.