I only feel this way about NFL players for some reason.
Same here.
The other sports aren't as physical and I'm sure the average career and earnings are far lower in the NFL for the lower-tier players than if you compared it to other sports.
Footballers can often go 10+ years and make a decent living (£500+/week is nearly £30k/year) playing in the lower leagues, and there are
many lower leagues and many other countries where they can play football. If you make a go for the NFL and fail, you're pretty much done. Basketball also has a worldwide appeal which means Americans can move to Europe, South America and Asia (even Southeast Asia has its own cross-country basketball league).
There's also the long-term effects of continued physical abuse which you suffer from playing in the NFL. No other sport has as devastating a long-term effect as the NFL; concussions, brain damage, speech impairment etc. are all pretty much common for ex-NFL players. I'm sure the most that athletes who play other sports go through might be some chronic back problems, no cartilage in the knees etc.
Although some might have serious issues, they're mostly physical issues that can be rehabilitated and/or would not significantly affect a person living a normal working life. The s*** that NFL players end up with makes the whole adventure not worth it, imo.