There are some technology differences between Uverse DSL and TWC/Spectrum internet service that make the raw Mbps numbers not directly comparable.
DSL uses a copper pair (telephone lines) between you and the aggregation point that is entirely yours. There is a strong distance dependence, which is why some people can get higher speeds but a neighbor a few doors down can't. Your speed is a function of what max level you pay for and what can be sent down the unshared copper pair. While there are some electrical noise issues that can degrade performance, you will mostly get what you pay, as AT&T does a decent job not selling a service they can't deliver. At the far end of the copper pair, the data is aggregated on a fiber network. The downside when you have Uverse internet and TV (and phone) is the single bandwidth is shared between your tv, phone, and internet, with the TV and phone getting priority, but they do a decent job of accounting for that in determining your max internet speed package.
Cable uses a coax cable that is shared with your neighbors. The coax then ends up being aggregated with other groups on neighbors and put on the fiber network. Depending on how heavily oversubscribed, people can see a drop off from the max rate they pay for when all their neighbors come home and start using the internet. This use to be a very noticeable problem, but as speeds have increased, I'm not sure how noticeable it still is.
In truth, you are aggregated with your neighbors somewhere along the way, either at the coax with cable or at the fiber with DSL, and there is the potential that the service is oversubscribed to some extent and performance would degrade if everyone tried to max their internet usage at the same time.
As the providers roll out fiber to the home, the distance on the old tech (coax and twisted pair) is shortened and thus speeds can drastically increase for DSL and the sharing of the coax decreases with cable. Thus both services can push gigabit after the neighborhood is rewired.
Google fiber doesn't have the legacy network, so they have to wire the neighborhood from scratch. Same issues for all of them, except DSL and cable can provide service now before upgrade and google can't provide anything until they lay the fiber.