I measure the size of a game by the studio/people behind it. There's a difference between a game made by one person trying to push their game, to studios of ten or more people, to Sony. Also, what you have discussed in this threat has make me thing a lot of the rating of itch. Several good stuff to take in account.
Viewing post in Dilemma with rating games here
You might want to compare by relative popularity. I like to use the follower count as a measure for that. There are accounts with 5 digit followers. But also the 4 and upper 3 digit follwers are "big". Many of those are individual game developers or amateurs. To the contrary I see actual game studios with less followers.
This is of course relative to itch and says little about success of the game developer or studio elsewhere.