There was the dot com bubble burst in 2000, so there has actually been one. A few years after the 2008 crash sounds about right to when people started talking about tech bubbles again to me.
I lived and worked through it and I’ve not seen tech slow down measurably, even then. There was a correction, and a shake out, but then it picked up basically where it left off and shot up. There have been other busts over the last 70 years but they’re more like a system that overheats, slows, then resumes.
All the signs were there for everyone to see in the 2000 Dotcom Dotbomb. The root problem was a bunch of investors wildly investing in crappy tech companies, like tinder for cats. There were toxic assets, huge and publicly visible waste, low product output.
This time, there is a lot more growth from many companies but we also see the results of that work, products and services exist as a result. There is waste but not like in 2000.