This.

There are often actual limits to what can be done, and there are practical limits. Especially in the early days of a technology it's really hard to understand which limits are actual limits, practical limits or only short-term limits.

For example, in the 1800s, people thought that going faster than 30km/h would pose permanent health risks and wouldn't be practical at all. We now know that 30km/h isn't fast at all, but we do know that 1300km/h is pretty much the hard speed limit for land travel and that 200-300km/h is the practical limit for land travel (above that it becomes so power-inefficient and so dangerous that there's hardly a point).

So when looking at the technology in an early state, it's really hard to know what kind of limit you have hit.