Ohhh, none. In truth I was being a bit glib about presenting a speculation: perhaps they progress along a different axis of cultural or intellectual advancement, one that can't be measured by technological achievements.
Although I'd also say, though it isn't direct evidence per se, that consistent evasion of 50+ years of our efforts to prove their existence demonstrates a certain superior intellect.
But consider it this way: some humans have achieved some remarkable things through meditation, controlling heart rate or body temperature for example. Perhaps there are powers of mind far beyond our comprehension, and sasquatch, not being so consumed with material problem solving by necessity, progressed along that path perpendicular to our own.
There are reasons to think that could be the case. The Native Americans seem to think along these lines, and habituators frequently talk about them this way too. There are also those who claim experiences with sasquatch that transcend what we think of as "normal," and we insist that those posts get their own home down below the general section. I think MIB's point is astute and that's kind of been my creeping realization with myself over the past year or two: who am I to scoff at others' alleged experiences, when I seven or eight years ago would've scoffed at my own experiences since then?
One final line of reasoning on intelligence vs culture: the Sierra Sounds and their spoken language. This is evidence-based, and it certainly indicates we're dealing with something way beyond extant great apes. If they have a spoken language, is it reasonable to expect that they produce no cultural artifacts because they're incapable? If they're too primitive of mind to produce technology, why do they seem to understand the uses of our own, such as guns and cameras? If they do understand our technology to some extent through observation, why don't they try to emulate it? Why don't they steal a grill lighter and build a little fire to cook over?
My assertion is that they don't need to, they realize it would draw unwanted attention, and they choose not to.