Do yourself a favor, and don't pay that much attention, if any, to George Thorogood. There are far better examples of rooty bass playing in blues-derived rock to learn from, and about, let alone the "old testament". For one thing, the music in that video clip is Chuck Berry rock'n'roll, and while yes, Chuck's body of work was very much an outgrowth of the blues, it's not quite the same thing. To understand and feel the importance of 'the root' is essential, but there other little things that go with it. If you want to start in this realm, while working your way back(as you should)you'd be better served to absorb early ZZ Top, and nothing could be more root than this classic medley...
You will hear all sorts of people going on about Stevie Ray Vaughn, but almost a decade and a half earlier his bass player, Tommy Shannon, came to the limelight with another Texas master, Johnny Winter. This is their first album, and while not every tune is strictly 'root' playing, that foundation pulse is there...
You'll hear how there's still little runs leading to the root notes, and how often a bass player has to riff along with the guitarist to provide support. This album also exposes you to acoustic 'country' blues, which is important, but more on that later.
This band was the tipping point between authentic classic Chicago blues, and the blues rock era. While much can be said about the efforts of the British bands, they jumped into it wholeheartedly just a little later(with a few exceptions), and they had been learning it like a second language, whereas these guys were native speakers. Essential example of a root groove with a run-up line...
On the subject of the Brits, The Rolling Stones can mean many things to many people, but as far as interpreting the blues it can be said that they were one of the first UK bands to 'get it'; plenty of great examples mixed in with their early pop stuff. Here, Bill Wyman is for the most part firmly planted on the root..
As far as the source is concerned, unfortunately most of the historic footage available has less than stellar audio. In spite of that, here are some clips that show how it gets done...
You see, even if you're just laying into the root, and it is important, there are always some passing notes in between the chord changes. From there, you'll learn about walking, which is a complete thing in itself.
Studying the blues is a whole rabbit hole to go down, the best way to start is to stick with anything released on the Chess label, and branch out from there(The Three Kings: BB, Albert, & Freddie, for example). Don't ignore the country blues that came before; while usually lacking bass(upright, electric, or otherwise)there are all those primal rhythms to take in(and transfer to your bass playing style). On that note, study Willie Dixon. The fact that he only played upright is irrelevant. Bass notes are bass notes. Plus, he was the backbone of Chicago blues, the post-World War Two electrified style that is the template for practically all contemporary blues since, well, the fifties. Granted, there are all sorts of other blues subgenes, such as 'jump', which was the transition between swing and early rock'n'roll for example, but there's a lot of furious walking in that.