When is a tech "mainstream"?

At what point in the adoption cycle does any particular tech become common place or 'mainstream'?

Perhaps when a certain size user base is achieved.
Perhaps once a certain number of others adopt or 3rd parties expand upon the base tech.

or perhaps once the movies based on the tech start to be made.

Now that China has declared that BTC and Crypto is no illegal we can expect to see a big upsurge in adoption.
The release of a new movie in china is sure to boost that in October when it hits the cinemas.

Time will tell

https://coingape.com/adoption-first-ever-bitcoin-movie-storms-chinese-cinemas-october/