The other option is for a single bug in a single release to stay in your app reviews in perpetuity. Why would you want that, rather than give prospective customers the option to look at current vs old reviews?
Also, I would quibble with your description of it as 'resetting of visible app reviews' as the old reviews are still visible, they're just one tap away...
In a high volume market like the iOS app store this behavior might be OK. It shouldn't take too long to get back a few reviews to display a N stars rating. (Just guessing, have no iOS apps in the store).
But in a low volume market like the Mac App Store it takes anywhere from a few weeks to months to get 5 reviews after an update. (Or even years in non US stores).
I made the experience that updating a well reviewed Mac app leads to a drop in sales until you get back to at least 5 ratings. (You need at least 5 ratings to display the average rating in search results and category lists in the Mac App Store).
This is a big incentive to keep updates back until it is really necessary to release them.
Yup. For that reason I've stopped releasing often and now have a beta program independent of the app store that people can opt into from the app itself.
Also, I would quibble with your description of it as 'resetting of visible app reviews' as the old reviews are still visible, they're just one tap away...