One would think, if what they produced was snake oil, the company would have not lasted this long...
That's a rather naive assessment.
You could say "If the claims of the homeopaths weren't true, you wouldn't expect them to have lasted this long..."
Or "If astrology didn't work, it wouldn't have lasted this long..."
Beliefs based on subjectivity, imagination and misconstrual of evidence can last a loooong time. Indefinitely, it seems.
That doesn't entail SR is snake oil; only that your point isn't terribly strong.