Old ideas we should bring back
Yes, walking used to be a spectator sport. A modern version might include trackers and cameras on each competitor so people could track them online and see what they're seeing in real-time. The walking routes could be chosen for how interesting they are, such as Antarctica, the Amazon rainforest, or the Sahara desert.
2. Building your own house
I think it was Kevin Kelly who I once heard on a podcast say that everyone should build their own house once in their lifetime. People used to do this all the time, but nobody does it anymore. It's a lot of planning and work, but if you actually designed and built your own house, wouldn't you just want to live in it forever? Maybe software could be developed to make it easy to design your own home and order it online to be built-to-order.
Maybe shopping malls are dying in the United States because they don't have arcades anymore. Going to the mall used to be appealing because you could shop, eat, and be entertained. I loved going to the Echelon Mall in New Jersey in the 90's, because they had this massive arcade called Exhilarama that had games, bumper cars, virtual reality, and laser tag. They also had a separate laser tag place that was converted from a defunct department store that was just awesome. Perhaps a modern version of the arcade would provide high-tech equipment for people to explore different proprietary metaverse attractions.
4. High fantasy
Here's an unpopular idea: I don't like Star Wars. In fact, I watched Episode II (Clone Wars) and III (Revenge of the Sith) for the first time last week with my kids, and it was okay. But I love me some Lord of the Rings, The Chronicles of Narnia, Game of Thrones, and Dungeons & Dragons. Yes, I'm that type of geek. I even named my three kids after fantasy novel characters... but perhaps we'll discuss that another time. I'd like to see fantasy books, movies, and games become big again.
5. Board games
Video games and the Internet have taken over and rendered board games obsolete. I'm sad about that. There was a certain social aspect to board games that can't be replicated with video games, even multiplayer video games. In their heyday, board games were awesome. Check out these old TV commercials for Fireball Island and Hero Quest. There may still be a market for board games that have a lot of props and visual effects (for example, the successful crowdfunding campaign to bring back Hero Quest). Maybe we can even add modern gimmicks to board games, like LED lights, sound effects, and app integrations.
6. Exploring the oceans
Why are we so focused on exploring Mars when we haven't even explored 99% of our oceans yet? I remember in the 80's everyone wanted to be a marine biologist or an oceanographer like Jacques Cousteau. We should explore the deepest parts of our oceans and perhaps build a few underwater colonies before we tackle more difficult things like colonizing Mars.
In the olden days before universities opened up to common peasants, people were educated by apprenticeships. Apprenticeships kind of died off when everyone started going to college. We should bring them back, because I think people would learn a lot more and go more in-depth into their craft if they had a mentor to teach them all the real-world tricks of the trade one-on-one. How would that work today? Maybe people who become highly skilled in their trade can get authorized by their trade organization to take on a certain number of apprentices, who would receive a certificate or diploma when the mentor deems them "ready." For an extra modern twist, the certificate or diploma might be in the form of an NFT.