No recent reviews is not a reason to worry persay. It just does not help you know what to expect today. You may get the same level or less service.
If a place is still open after a long period without reviews it may just mean that all is well and the regulars are trying to help the place fly UTR.
If something has changed usually somone will say "they closed" or "they stopped doing this or that". Absent those types of reviews or posts, I would assume all is well and visit, if I found out it was not the same I would report back.