Pretty sure humans always did innovate as you said yes. And I mean, you can just look at modern humans for that, were not fundamentally biologically different to the humans back then. And we loooove slang, and trying out new things, and being curious, and learning. And we need no external motive to this
But you need to think yourself in their position, they wouldn't have known the limits of technology, they wouldn't have known that anything in our modern world was possible. They had nothing to go off on. All they had were rocks and wood and plants, and maybe fire (that's not hot enough to melt metal)
There is such a long way to get to any technological point resembling anything close to the industrial revolution it's not strange that it took a long time. Or, hell, even agriculture. A big problem with agriculture was that it didn't improve the well-being of the farmers in the short-term (and the long-term is beyond their lifespan), so it wasn't just a purely technological thing. It needed the correct set of external factors for it to be preferable to hunting and gathering.
I'd wager to guess that if you had the humans that were back then, but instead they just knew that our modern world is possible, you'd see a hell of a lot more progress happening a lot quicker. Because then it wouldn't be a question of whether gears, or electricity, or medicine, or a complete understanding of the world was possible, but instead how.