I believe with Steam you at least have to give comment on your recommendation, so that people can 'review' the reviews. That of course does not change how the rating system works and that those ratings will always be a mix between subjective opinion and objective analysis.
The system could also be expanded to make it more custom-tailored and fair. But that is a topic that could be discussed a lot. Some had considered a middle option to choose instead of just recommend or not. Maybe giving viewers some tags or filtering the reviews based on the collected account interests could also be a viable solution.
In regards to itch.io, I get why they have 'limited' the reviews here - but it also makes their function just that - limited. Maybe they could also expand it for users to check some questions when rating, like 'What did you like/not like - Gameplay - Presentation - etc., or simply giving stars to more categories and then summarizing this to give a better insight when checking the review section for a user.
Then again, it seems not a lot of people are using the rating system to much extent anyway. And you can also always just open up your comment section if you want people to share their opinion on your product. The system might not be perfect, but I guess it is an additional thing to serve its purpose for users and when considering results in the search system.