Cable channels were themed, but cable packages were not. There was not a realistic chance of that changing. The technology was not good enough for that. If I recall correctly, analog cable depended upon bandpass filters that were rarely perfect so it was best to group channels in blocks. When digital cable entered the fray, the other motivation entered the forefront: it simply didn't make business sense to sell individual channels.

When it comes to that business sense, we probably have the closest thing to perfection today. Streaming services are forced to compete against each other, with the only real constraints being the cost/restrictions of licensing content and the cost of distribution (i.e. not controlling infrastructure to the home). It is very easy and relatively inexpensive to pick and choose, provided that you are willing to defer your viewing. You also have the choice between large streaming services that offer a broad range of genres and smaller ones that offer more specialized programming.

Yes, that closest thing to perfection is far from perfect. On the other hand, I very much doubt that we are going to get anything closer unless we are willing to pay the price.