The age of the experiments is not of importance. It's all about whether the experiments deliver consistent results, whether they make verifiable predictions, whether they are falsifiable etc. Einsteins theories, while obviously not 100% perfect, have been corroborated consistently, they've made accurate predictions and have been widely verified by the scientific community and have thus held up to this day.
Rowbothams ramblings are a different story altogether. His theories don't stand up to scrutiny, he completely ignored (or made false assuptions/claims about) certain factors (such as sunrise and sunset, the southern hemisphere etc.) and his experiments could not be consistently repeated by the scientific community.