That is text reviews with 1000 symbols limit. Even if you take all reviews on platform you most likely would not get even 1 megabyte, and it is not mentioning compression that they (most likely) use for map files ¯\_(ツ)_/¯ .
So I highly doubt that cutting off reviews will do much in terms of saving space.










It still going to be small, again, it is just a text reviews, no pictures or anything (no comments even) with max of 1000 symbols per review.
Assuming they use utf8 for strings, so the biggest review will take 1 kilobyte at most. Considering most reviews are even less then 2 whole sentences, I doubt it will take much in near… Decade if not more (at which time we would most likely die in world war or something).
If we take around ~6.5k reviews (based on number in an article), it would mean we would have ~6.5 megabytes for entire world at most + some metadata (but we would not, considering most of reviews are really brief, so I would say we would sit around half of that size) + compressed + divided for entire world, so at most we would have shaved maybe up to hundred of kilobytes (in maybe several years if we would even have enough of reviews) per country/region/state, which does not sound a lot, considering it would require quite a lot of effort to reorganise stuff. So eh, I do not know.