I think OP's questions are in good faith-- for those who lived "in the Resistance" as it was happening, the events probably seem closer, but it's been more than ten years and there are a lot of people who are analyzing the events after the fact, as part of traditionalist history.
While it is true that the SSPX did not reach an open and formal agreement with modernist Rome, it is equally true that the SSPX has slid leftward, and continues to slide leftward, since ~2012 (I agree with Britpapist that this leftward slide actually dates to ABL's death-- but it's accelerated over the last 10-15 years). The Resistance as originally formulated was motivated by resistance to and rejection of any deal, but the spirit of it was also opposed to increased liberalization of the SSPX whether or not a deal was struck.
Of course, one can point to lots of good priests within the SSPX who are not liberal and who have resisted liberalization. But considered corporately, the SSPX as measured by its messaging, its priestly formation, its politicking, what it will and won't criticize, has become largely indistinguishable from the Indult groups. It (the SSPX) maintains one very significant difference from the Indult groups which is that the lion's share of its priests are still validly ordained. Aside from that (which is no small issue), it's hard to tell the difference between the SSPX and the FSSP.
I've spent some time thinking about the nature of the term/label "SSPX Resistance" as a descriptor for a specific group, and I think the label has expired. The label came about as a way of describing a rather significant exodus of priests all leaving the SSPX (or being expelled) at around the same time, for the same reason: they were opposed to Fellay's intention of striking a deal with modernist Rome. And at the beginning, the label made sense. As time went on and the deal was not made, and as priests had a chance to reconsider various things (like whether they wanted to be part of a group at all, or whether they wanted to maintain an R&R position, or if they did want a group whether it should be headed by Bishop Williamson or someone else, etc.), the label basically became a catch-all for any priest that was left/was expelled from the SSPX due to its liberalization. But that's a label so stretchy it starts to lose its usefulness, since it's referring to priests who are sedes and non-sedes, priests who want an organization and priests who want a loose affiliation, priests who "red light" the SSPX and priests who don't, etc.
The more and more time passed, the more clear it became that there really was no corporate body that could be called "the Resistance" because there was just too much diversity of opinion and no real corporate unity among them. This, of course, does not stop people from still talking about "the Resistance" as though it is some corporate body, but I personally don't think it's any more useful than referring to "The (Oyster Bay) Nine" as though that is some corporate body. Like The Nine, the Resistance is really an historical artifact. Some people who belonged to it are still alive, some aren't, some still think exactly what they thought at the time the group existed in corporate unity while some have changed their mind.
But in present day, there is no "The Nine"-- there's MHTS, SGG, the SSPV, and a few independent priests. Likewise in present day there is no "SSPX Resistance"-- there's the SJAM, Dom Tomas Aquinas's group, +Williamson's independent bishops, a variety of independent priests, etc. Mind you I am only making a claim about the usefulness of the label as a descriptor of a corporate body. If you can do a "where are they now?" retrospective on the majority of the members of a group, that's proof that the group just doesn't exist in any meaningful way.
Topic: Why is the SSPX Resistance still a thing? (Read 8273 times)