There's definitely a degree of that. When I was in the fairs, the winning kids were often the ones with the giant posters 3 stories tall working in a lab no on else had access to. I had to beg my school for a $100 robot controller to do my project, and my truck driver dad and SAHM didn't have access to a fancy lab where I could do experiments.
Still, although it's hard to compete with the upper echelons, you can still get results that land you in schools you wouldn't have gotten into otherwise. 100% the reason I got into CMU was my science fair work. I personally never got 1st place at science fair, but I won awards (there's tons of special category awards) and was competitive, and others who didn't have access to a big research lab did get first place. So, yes, it's not exactly fair but at the same time it doesn't mean you're out of the competition if you don't have access to those privileges.
Still, although it's hard to compete with the upper echelons, you can still get results that land you in schools you wouldn't have gotten into otherwise. 100% the reason I got into CMU was my science fair work. I personally never got 1st place at science fair, but I won awards (there's tons of special category awards) and was competitive, and others who didn't have access to a big research lab did get first place. So, yes, it's not exactly fair but at the same time it doesn't mean you're out of the competition if you don't have access to those privileges.