I've hired someone that didn't solve a specific technical problem.

If they are able to walk through what they are doing and it shows the capability to do the expected tasks, why would you exclude them for failing to 'solve' some specific task? We are generally hiring for overall capabilities, not the ability to solve one specific problem.

Generally my methodology for working through these kinds of things during hiring now days focuses more on the code review side of things. I started doing that 5+ years ago at this point. That's actually fortuitous given the fact that reviewing code in the age of AI Coding Assistants has become so much more important.

Anyway, a sample size of 1 here refutes the assertion that someone's never been hired even when failing to solve a technical interview problem. FWIW, they turned out to be an absolute beast of a developer when they joined the team.