I had a similar experience interviewing after being off the job market for a quiet a few years: You will be rusty initially, but then you will pick up steam.
Just like in your "real life", solving interview problems is not about reinventing the wheel with 100% custom solution, its about pattern recognition where the pattern is a problem you know a solution for. The more problems you solve(and possibly fail) the more data your internal pattern recognition algorithm(your brain) has to help you with the solution.
I dont see it as gaming the system, I see it as being able to prove that you are capable of problem solving.
Yeah, it's a positive signal that someone was able to pick up from past failed interviews. It's a weak filter, but it's fine to have. From there, it's best to work with the person on short projects, and then hire them as a contractor to find out if they're a culture match and can solve the problems you're facing at an acceptable rate and in a maintainable way before hiring them on as an employee.
Just like in your "real life", solving interview problems is not about reinventing the wheel with 100% custom solution, its about pattern recognition where the pattern is a problem you know a solution for. The more problems you solve(and possibly fail) the more data your internal pattern recognition algorithm(your brain) has to help you with the solution.
I dont see it as gaming the system, I see it as being able to prove that you are capable of problem solving.