The OP question is kind of like comparing apples and oranges, but here are some facts (general pro opinion ) about poker.
nl poker has a lower variance than fixed limit.
ring games are more profitable than tournies.
between 3-5% of poker players are long term winners.
online is more profitable than b&m in general.
nl has a different skill set than fixed, some say its harder than fixed limit some say fixed is harder. nl has a few hard choices that make a big difference, fixed has many hard choices that make a small difference. pl is the most skilled form of poker.
the games that offer the lowest andvantage between the sharks and fish are the games that have the most fish in them.

Which presents a quandry for the shark.
i.e. worst players are in sit and goes, because it is very hard for the shark to make a living on this structure. few fish in
PLO8, but the fish that wander in have no chance.
I would think all forms of poker have a lower variance than capping sports. Assuming you have a substantial advantage over the game you play. Money management is much easier.
If you follow kelly for both options (nl poker, cap sb) and are very good at both, your bankroll for poker would be much less for the same hourly earnings. Sb has more potential hourly earnings with a mega bankroll I would speculate. Very Very Very few poker pros make more than a ev/hr of $150.
Anyone thinking of doing the poker thing take this advice.
Start off with $50 and start playing microstakes poker. (lowest you can find.) Let your bankroll set the stakes you play. If you lack the patience to play at these stakes, maybe poker is not for you.
just my 2cents.

GL
p.s. I am somthing like a dolphin in sb so take anything i say about sb with a grain of salt.