The point about having an economically viable use-case is very relevant in today's times. The Romans didn't need engines because they had slaves. I have a hunch that the abundance of "VC money" and high cost of living in rich Western countries actually stifles the demand for many types of inventions and services. There is simply no need for, and no ability to run, smaller, less profitable tools and services due to the demand and existence of massive amounts of financial capital.

One of the first things I noticed when I moved to Ukraine from North America, a country much poorer in comparison, is the existence of many types of shops and services that would simply be "not worth the money" in North America. The abundance of small artisan coffee shops, mom-and-pop tool stores, custom furniture manufacturers, metal workers, etc. I was shocked to find out, when I ordered an office table on Rozetka (Ukraine's version of Amazon), that the seller reached out to me and asked me what height I would like the metal legs to be, because these tables were built-on-order, not mass-produced and stored in inventory, and so it could be custom-built to specification. And then I found out custom-built furniture is totally a thing here. And the cost was peanuts. I have friends in Kharkiv that own small mom-and-pop metal fabs that could build anything you want with a CNC machine or lathe, and it is profitable to operate these types of factories because the cost of running the entire factory with labour and machines is under $10k / month.

Similarly, because of the low cost and high availability of software engineering talent, and the lack of VC money to drive up the cost of engineers, the average quality of software here in Ukraine is much higher. As a programmer, I immediately noticed that the quality and availability of small custom apps for all sorts of stores and services. Kyiv the municipality has a very well-built city-app that integrates with essential city services, including parking and traffic enforcement. If your car is towed by the city, or you get a ticket, you get a notification on your phone, and you can pay and pick up your car from the holding lot by showing a QR-code to police. The app is extremely well-built. Compare that level of technical integration and efficiency with most Western governments' apps, like the infamous CBSA scandal, or Obama's failed Healthcare.gov boondoggle. Software in Ukraine is really, really good, from my barbershop to the the bank. I have a startup in the fintech sector, and you cannot compare the quality and feature-richness of banking apps in Ukraine to Canada or the US.

Necessity is the mother of invention.