The problem with bubble prediction is the perverse incentives. If you say there is no bubble, you look like an ignorant groupie. If you say there is a bubble, even if nothing happens, you can just say "you guys got real lucky this time".
That's why I only consider the opinions of people who put their money where their mouth is. Having skin in the game usually tends to lend the proper incentive to having an informed and insightful opinion. Usually, but not always.
https://hn.algolia.com/?query=tech%20bubble&sort=byPopularit...
Someone will get the timing right though, and go on to do a number of interviews and maybe even publish a book.