Most third-party internet-based streaming solutions are overlaid on top of a point-to-point network, while broadcast is one-to-many, and even cable tends to use multicast within the cable provider's network.
You have potentially different problems, e.g. limited bandwidth / spectrum. If, say, there are multiple games going on at the same time, you can only watch whichever feed the broadcaster decides to air. And, of course, regardless of the technology in use, there are matters of acquiring rights for various events. One benefit of internet-based streaming is that one service can acquire the rights and be able to reach everyone, whereas an individual cable provider might only reach its direct subscribers.
On cable(terrestrial is entirely different) even the bandwidth or spectrum is less limiting for broadcasting multiple games. Hard thing is the other parts of production, like cameras, live-directing and live commentary. Adding new channels is less challenging than actual producing content at expected level there.
Most third-party internet-based streaming solutions are overlaid on top of a point-to-point network, while broadcast is one-to-many, and even cable tends to use multicast within the cable provider's network.
You have potentially different problems, e.g. limited bandwidth / spectrum. If, say, there are multiple games going on at the same time, you can only watch whichever feed the broadcaster decides to air. And, of course, regardless of the technology in use, there are matters of acquiring rights for various events. One benefit of internet-based streaming is that one service can acquire the rights and be able to reach everyone, whereas an individual cable provider might only reach its direct subscribers.