The opposite is also a problem: a property management company I had issues with changed their name three times in the 24 months I was a customer. Each time they get a brand new slate, and can have reviews for the old company on the new page removed under the Yelp TOS, since if you say in your review you're not a customer, you're admitting to violating Yelp's review guidelines.
(So you can't type in the address of the building and see bad reviews under different name for same addy. To be fair, the condo board and neighbors were nice, but as a renter I can't do repairs or replace broken appliances.)
At many smaller companies with only a few submitted salaries, the problem is much worse. I've received offers for 2.5X the quoted salary for the same position glassdoor supposedly had 10 submitted salaries for (bay area).
None of these review aggregators are incentivized to dump old reviews and make it look like they have less data than their competitors. Inevitably, consumers will start trusting reviews less and less...similar to what has happened on Amazon.
Steam solves this quite well by showing recent and all-time ratings. After all, one future patch can make or break a game.
Well, it makes sense doesn't it? When you buy a restaurant you get to keep the name, location, word of mouth, etc. Makes sense you also keep the reviews.
New owners not having the same standards and ethics is more common than not. (Can go both ways of course but nevertheless, the ratings should not pass over, it makes zero sense.)
After some years the restaurant closed for renovation, and when it reopened there were completely different people working there, and the food was way worse. It was probably sold or went under new management, though they kept the name. So all the reviews this place had gotten over the years were really no longer relevant, as it was effectively a new restaurant. Yet all the Yelp reviews remained.