Well, gee, since we're talking as a career, then you're talking about a poverty level career for even the most talented player.
vas majority of practitioners are like me - we do it as a non-career, for the fun and education of it. If I were to start as a kid (I was a swimmer as a kid - totally wrong answer for me as it killed my body by the time I was 18), I'd start with judo. Why? Because what kid doesn't dream of Olympic gold? or the front of a Wheaties box, whether they like Wheaties or not? Bjj just doesn't have that cache.
Second, judo, because if you go UFC after your highly competitive judo career is over or when you want to make some actual money, then judo's a lot better than bjj. Bjj athletes in the UFC are a dime a dozen. Judoka are much rarer. So, there's the cache of that, the unpredictability of being a judoka in a largely bjj and boxing field. So, if you're going to want to make actual money, then being able to stand out because of a judo background is very helpful.
Third, education. There are still a few schools in the US that offer scholarships to judoka. Few and far between, sure, but the same cannot be said about bjj.
Fourth, when I realize I'm never going to be elite (as the vast majority of us will realize), and I won't even get one of those scholarships to college, there are still college level club programs at a great many schools. They're inexpensive, well established, and at schools ranking from Harvard/U of Chicago down to the community college level. If I go the military route, I can find dojo on a ton of bases. If I take a semester abroad or wind up at a military base overseas, I can find judo. Can't necessarily find a bjj club (though it's getting more popular, but once you throw in the pedigree snobbery, it becomes problematic).
Again, as a female, most of the judo dojo I've been in are far more inviting than the bjj dojo I've been in. In judo dojo, the only people who are afraid to practice with me are brand new white belts who don't know better. In bjj dojo, that can't be said - there's still too much testosterone related ego around to make it a great environment for me.
So, once I grow older, have a career, have a spouse, start having kids, I'm still going to be pleased with judo as a choice. Why? less expensive, more family oriented clubs, and the ability to get transferred without having to worry about whether or not the local judo dojo is of the right lineage. Ideally, with the big 3 orgs working together, I can easily transfer rank from JA to JF or whatever, and continue on with my journey. So can my spouse and kids. We can go to shiai when we want to, and only have to worry about having a decent white gi. Blah, blah, blah, blah, blah.
But, then Nina Cutro Kelly is a great example of dualing in judo a sambo.
But, hey, we're talking making money. The overwhelming majority of even the most elite level practitioners don't make money at either endeavor unless a part of the Japanese team or a country that actually supports its athletes.