I know it's been done to death, but whenever someone pulls off such a controlled tone with a cheap bass, it suprising to me.
The pickups are Dimarzios in her bass, and she's running into a decent compressor pedal and then into an old Fender amp. It is also quite a basic bass tone so with that setup an SX and a Fender CS masterbuilt (etc...) '64 Jazz bass would sound pretty much the same. Flats, probably high action, foam mute, good pickups, good compressor and good amp.
As I mentioned (I think?) in the other Khruangbin thread on these forums, the guitarist in 'The Grateful Shred' tribute band absolutely kills it with a backwards Squier Strat that looks like it was rescued from the pawnbrokers. Go on the Grateful Dead forums and you have guys on there with the full reproduction Jerry Garcia rigs, all true bypass, onboard effects loops (etc,
ad nauseum), and they can't play their way out of a paper bag. There will always be a case for 'the player, not the gear'. And there will be bad musicians with good gear, good musicians with good gear, bad musicians with bad gear....
In keeping with the theme of this thread, I reckon you could probably get a good approximation of Jamerson's tone out of an SX P bass. I find it a bit silly that people want to drill right down to reproduction '60s P bass pickups with the correct coloured bobbin and cloth wires to get into Jamerson country, because the basic tone is a dull thump. Listen to the isolated Jamerson basslines and there is a sort of interesting kettledrum-like resonance and 'boing' to some of the notes that maybe isn't the nicest. However it sounds great in a full band mix (with horn section, three guitars on different flavours of rhythm, two percussionists); especially when that is a hot mono Motown mix. Can you hear the reproduction pre-CBS dust on the polepieces in that sort of mix? Nah! An SX would get the job done and, if not, simply buy a used SPB-1 pickup and start over. Focussing in on the tone of the bassist in Khruangbin, George Porter Jr, Jamerson (etc) is missing the point. They had a Vanilla tone. The interesting stuff is in what they actually play, or played, as musicians. If you put gear before musicianship then this message will clearly be getting lost.
And... none of this means that SX basses are good, necessarily, which I think is where OP is going with this one. I've played a few SX instruments and never been that impressed with them. I reckon Squier build a better bass for the buck! Swap out key hardware and components with better