Even if it has 4.8 and 7000 reviews it's often fake 4.8 because the reviews are botted / paid / dark patterned (e.g. when you pop up star rating on your users and beg them "rate the app plz" and when the users tap anything but 5 stars you say "k, ty" and keep those "bad" reviews for yourself)

That was just an example to communicate my idea: a better way to validate authenticity of the app could and should be used.

But to your point specifically, Play store and App Store have APIs to rate from within the app: when the pop up shows, app author does not have an option to avoid getting a 1-star rating (they are also time-restricted, eg. at most once every 180 days for Apple IIRC).

What devs do though, is to preempt it with "Are you enjoying our app?", and only giving you a formal rating pop-up if you answer "Yes".