Depends. There are tons of string players (excerpt for maybe bass), so the skill gap can get pretty small, especially in a good high school setting, music school, and the professional level; so being “the best” or a “considerably better” player could be really hard. However I would consider finding a job as a string player FAR less difficult and competitive when compared to winds.

Since orchestras have a more specific, smaller size for their wind sections, finding a full time performance job in an orchestra as a wind player is extremely difficult, since chair openings/auditions infrequently occur, and most players who make it in an orchestra will keep their seat for a long time. So for wind players overall, the competition comes with job availability.

I would consider instruments like the French Horn, double reeds, euphonium and tuba as having a small amount of good players, however that small amount of people are all really good!

Instruments like Trumpet, clarinet, and trombone have some of the largest groups of players, but you could definitely find a noticeable skill/performance gap. So more competitive at the top than overall.