do chess pros actually make a decent living?
compared with a sports ball player I imagine sponsorhip opportunities are smaller
Depends where they live or are prepared to play. Matthew Sadler was something like no. 4 in the world when he said it didn't pay nearly enough and he got a job with Hewlett Packard. OTOH Kasparov is fabulously wealthy* and when Nigel Short lost the World Championship to him his loser's money was more than Steve Davis's for winning the World Snooker Championship the same year (£1.4m compared to £1.2m IIRC).
The top UK grandmasters used to play in the Bundeslige as the pay was good. When my daughters were young they used to get asked to play in the 4 Nations Chess League when it was in its infancy. Some top players got paid reasonably well by their teams' sponsors. OTOH I recall giving one very strong player and published chess author a lift from Essex to Birmingham one weekend and he went ballistic when I asked him for what I thought was a reasonable contribution to my fuel costs. That might just have been him being a skinflint though. He also teaches law in a university.
*Or was before the Lehmann Bros crash. I think he lost a great deal then.