Most folks who can't weld simply lack confidence and then basic knowledge.
I took a welding class years ago at the local high school. Reason was because I used things on the weekend and often something would need a repair. I couldn't do the repair and couldn't get it to some one who could during the week.
There were seven guys in the class and one of them was a professional welder. I'm thinking what is he doing here, or why am I here? So my skepticism and confidence went even lower!
First thing was a bunch of safety info/procedures. Then everyone got a work area, and some equipment and some instructions on using it. Had a piece of metal and asked to just weld a bead to see what we could do. I remember the instructor went to each table and watched for a bit then made a comment. When he got to me and watched for a bit he said, "You have a steady hand, you'll do fine." That statement changed my total outlook on welding. I knew I could do OK from then on. Just need to listen, practice, learn what needed to be corrected, and keep going.
I'll say it again, if you have a steady hand you can weld!