It can definitely pay for itself, if nothing else, eventually. It can take a bit to run across class 4 or 5 data, but even the smaller stuff is usually at least a few thousand. If you're surveying as you explore (particularly if you're doing it on top of bounty hunting, checking nearby systems after hitting one, or similar stuff for probe drop missions), you can end up raking in a good fair amount.
Currently doing a new mod-enabled run, but my other one (the legion/paragon monstrosity) cleared over a million on two separate distant-system runabouts. Primary reason I could take those two in when I found 'em, since affording it was totally a thing. Few class IV and/or V survey datas, couple of alpha AI cores,* the smattering of <other stuff>, start your exploration on a multi-week out bounty so you can guarantee a couple dozen k when you get back, it can add up pretty quick. You definitely need good support ships if you're going for that, though, and/or be willing to pick up derelicts as you go along to net more cargo/fuel space. Plenty of cargo space and fuel, lots of crew (more for scavenging than surveying, though you need hundreds for the biggest stuff regardless).
Incidentally, small exploration tip -- if you don't need to be moving hyper quick (and even if you might, since you can easily eject the excess) going over weight with supplies (specifically the supply item) is basically without downside. It massively inflates your maintenance supply costs, but all that really means is the problem is self-solving and in the interim you can often enough fix up stuff while they're draining back down to equilibrium. Kinda' useful if you're hitting ships or debris fields along the way.
... though that said, unless you're using tugs, I would probably recommend avoiding the biggest fuel/crew/cargo transport ships. Their burn limit is a total nuisance otherwise. Think they're better off if you are using tugs, but probably don't bother otherwise.
* Give them to tri-tach if you can and you're after cash, by the by. Assuming it's not random per game, they apparently give double bounty for AI cores (i.e. 300k for a single alpha), which can rapidly become hella' bank if you're faffing around the outer systems hitting drone fleets and stations.