Why would TV need speakers? It's almost the same argument as with the smart TVs. I have a nice set of standalone speakers, why would I want to pay for the crappy speakers in a TV?
A lot of people don't care about using fancy speakers, are perfectly fine using the TV's crappy speakers, and would be much more pissed that the TV they bought is useless out of the box unless they buy speakers for it.
A lot of people don't care about using fancy streaming boxes, are perfectly fine using the TV's crappy smart features, and would be much more pissed that the TV they bought is useless out of the box unless they buy a streaming device for it.
Both of these things are true, and an argument for options.