I wish someone invented and actually sold tires which can't go flat. I don't mind if it makes the bike somewhat harder to ride. For short-distance trips (intra-city) this should be no problem, and could perhaps even save me a visit to the gym.
You think that because you don't realize how much harder it is. Like it takes significantly more power, turns much worse, and is much less comfortable.
Solid rubber tires exist though you are welcome to try!
I used the latter almost exclusively for years on thousands of miles of urban rides in Houston, and almost NEVER got a flat. I finally switched to a softer more supple tire when I bought some new wheels this summer, and they are WAY more comfortable and a bit faster, but I've had two flats since I bought the damn things.
It's all a tradeoff.
“Without an inner tube, you can run lower tyre pressures without the fear of a pinch flat, meaning a more comfortable ride with more grip. And if anything sharp does puncture the tyre, the liquid sealant inside will quickly fill any holes”
https://www.bikeradar.com/gear/article/best-road-bike-tyres-...
Over the past 5-10 years there's been a trend towards wider rims, thankfully. Before that, a lot of road bike frames couldn't even FIT a wheel over 25mm wide!
tubeless tires are commonly used along with sealant, which helps, but you can put sealant in a tire with tubes as well.