I would rewrite it as follows: " If a country had some good and working components a few years or centuries ago, it doesn't mean that it is still working fine today". E.g. If a country had a working legislative branch 50 years ago and it was one of the best at that time, it doesn't mean it is good or even working at all today, despite having the same name.

I'm implying that parliaments in multiple developed countries are rapidly devolving and ceding their powers and/or work to the unelected or unrelated officials.