The most obvious issue would be that the 6,000 figure in the article was pre-pandemic, so it might be much higher now.

Also, I don't know the economics of homelessness, but I feel like as supply of homeless shelters increased, demand for the beds would increase as well, right? How elastic is local demand, with people in RVs moving in/out of an area?

Not that it shouldn't be done, but it seems like if all it took to "solve" homelessness was building enough beds, we would already be doing that.