My take is this, and bear with me until the end; The Court is wildly conservative, not partisan. They're not on Trump's side. They owe him nothing.
See, once you're in for life, who gives a fuck? And that's very much the idea behind lifetime appointments. Sucks now, but I'm still down for it. Would we rather they be susceptible to political winds? (I'll take a Justice for all 12 circuit courts, at the least, please and thank you.)
Another thing that gets discounted, because they're in for life they owe nothing except to their legal legacy, their history. Most Justices, even the ones you hate, take this very, very seriously. Can't go any higher, their legacy is all they have left to define their life's work.
Thomas OTOH, is the most blatantly corrupt Justice I've seen in life, and I ain't a young 'un. This animal only cares about getting paid, no regard for his legacy, no shame. I see no reason or way he can be pressured out.