I don’t believe it’s indicative of anything, really. A traditional relationship with a publisher is going to involve them taking on responsibility for promoting the published game. They’ll typically invest money in getting the game to sell better and, as a result, will take a larger piece of the pie than services like Steam Greenlight, the Apple App Store, and the like, which are really little more than online distribution channels. While Steam or Apple might feature your app and give you some visibility, they have no obligation to and no real vested interest in making your game sell better than any other game. A publisher who takes your game on will - they’ll advertise, get you shelf space in stores, etc. It’s a very different situation than Steam Greenlight et al.
I think most publishing contracts are negotiated and the details typically kept private, but I’d be surprised if you’d get more than 50% of gross, and generally would expect you’d get less. The deal may be structured in any number of ways. Publishers may, for example, get “first money out” for their advertising expenses. Your cut may also be calculated based on net rather than gross (which you should avoid if possible, since the publisher typically gets to decide what expenses get taken into account for “net”). On the plus side, it’s not unheard of for publishers to pay some money up front, or help with some expenses. The better known your studio and franchise, the better the deal you’re likely to get. First game from a small studio? Don’t expect a great deal if you can even get a publisher interested.
Still, if you can get a publisher interested, it may be worth using them because you will probably sell more copies. But have a lawyer review any contract before you sign and run some scenarios using the contract terms to figure out how many more copies you’d have to sell to make more money. In the days of boxed software on shelves, publishers were really important. I honestly don’t know how important they are today.