@Leanne69 the written reviews are not being hidden from you; if you see no written reviews, then the guest has no written reviews. Airbnb has not changed the policy about being able to view written reviews, and you do not have to have Instant Book on or anything to be able to view a person's written reviews.
Ratings (the numeric star ratings) are only shown if you have Instant Book, but if the guest has no reviews, they also have no ratings.
If you are unsure about being able to see reviews, just click on any random person's profile here in the Community. You have no connection at all to them, but you can read their written reviews.
You may be seeing more people without reviews because Airbnb is expending a lot of effort and money to attract new people to book travel with Airbnb.