In terms of technical "next big thing" I think some of the better startups showed up in the smoke of the dot com crash and the 2008 crisis. There are so many areas where we are using Rube Goldberg contraptions, both in tooling and products, that I'm confident we will see progress. There's still a lot of low-hanging fruit out there. And maybe they were just needing some of the junk crops to be cleared to have space to grow.
There are so many small and medium sized businesses to whom the internet age has caused just more bureaucracy and admin. It may sound counterintuitive to someone from a high tech first world city, but in the developing world there are many businesses that are caught between old ways of doing things, lack of a tech-skilled workforce and modern expectations of what businesses should function like.
This often results in a huge overhead of business processes caught up in a hellhole of excel files, Asana cards, file servers, accounting software with paradigms out of the nineties and revenue services with expectations from the data age but still being run with a mentality from before the nineties.
All that while you guys (FAANG and the lot) talk about VR and self driving cars.
This is where tech could make a real tangible difference in productivity gains for millions, if not billions. But who is actually interested in that if you can build a rocket that lands by itself… (not meant cynically - just saying)