Who are you comparing to?
There has to be at least one ideal politician, otherwise I'd say the job is just inherently difficult. And hindsight is 20/20.
The job is inherently difficult, and I think a big problem is institutional decay/drift leading to a bad pipeline of leaders, which is why you have so many poor, weak, and ineffectual leaders serving back to back. The UK is a prime example of this, but I think all of Western societies are struggling with this to one degree or another.
Indeed hindsight is 20/20, and I won't pretend to have all the answers. I just personally think we have a particularly rotten batch of leaders which can't only be explained by the leaders themselves, but also by the institutions and policies which spawned those leaders.