Yes and no.
It's more about specialization and athletic caliber that are bigger players if you are trying to quantify which sports are actually tougher to get your child into the division I athletic scene. If your son is playing football or basketball, he is competing against overall better athletes across the board to get those scholarships that are available. So while the percentage of kids earning those scholarships is higher for those sports so is the talent pool that one is competing against to garner them. Secondly, the specialization sports (baseball, wrestling, golf, and tennis being primary ones) are largely driven by parental involvement, resources, and commitment to help increase those odds against a smaller pool of athletes. The baseball dad that decides at age 10 that Johnny is going to be in the cage 12 months a year is going to perform at a much higher level than a more talented athlete that doesn't focus on just baseball (yes obviously there's a component of talent trumping time, but it is by scale in many respects). The same goes for dad who has mats in his garage, private wrestling trainers, elite club participation, and traveling across the US 8-9 months a year that can greatly increase the odds of "making" his son into a possible top-tier wrestler. Golf and tennis seem to fall into similar situations. Less kids doing them and time and resources being able to scale long-term success rates.
Now if you want to tell me which of the sport's athletes work the hardest from age 4-18 to earn a scholarship (ie. toughest), it's wrestlers by a landslide.
