I mean, I think it just depends. I think if a 50 year old dude decided to buy $5K in equipment and do this, it wouldn't be profitable. However, I/the 2 photographers I knew have done this simply based on the fact that-
1) My camera only cost ~$600. It was something I bought because I wanted it, not because I thought I could make money. I used very basic editing software that came with my laptop.
2) I was in an environment when people wanted something a little better than iPhone pics, but as college kids, couldn't afford super expensive photography. It was saturated with a constantly renewing pool of engagements, proposals, young families, and seniors - big life moments that people wanted to capture, just not for $200.
3) My friends knew I was into photography, and I was approached by them (not the other way around). It was similar for the other two girls. Incidentally, all 3 of us were in sororities - haha. Then, word of mouth & Facebook did wonders for networking. One girl stayed well-connected with her old high school by recommendations alone and was always shooting senior portraits (guys and girls) as well as portraits (mostly girls) for her friends. As her friends got engaged/married, they called on her. Eventually she built up enough of a portfolio and had enough practice/experience for a stranger (me...) to hire for the wedding. And she did such a great job with it that I just recommended her to a friend of mine that is getting married in January, who is planning on hiring her now.
4) The other girls eventually took it to step 4 where they upgraded their equipment after making enough money. As they gained more experience and their calendars filled up, they were able to charge more and more.
I personally never charged anything as they were always just gifts for friends. The others slowly built it up from a side hustle/hobby into something that generated a little extra cash, and along the way they just practiced...a LOT. I'm definitely not saying, go out and buy a DSLR and try to turn it into a business. The reasons you stated are certainly barriers to doing so profitably. I just know that in the right circumstances (pool of potential clients, basic talent, appropriate pricing to what those people are willing to pay before they resort to DIY, building a reputation) it can be a side thing.