I'm an editor and writing coach who has worked with a lot of writers who have been published by both big and small publishers and I'm here to say that while I'm sure this does take place, writers usually take the responsibility of "blurbing" a fellow writer's work very seriously.

They do actually read the work and they do try to say something about it that a potential reader will find useful.

At least the writers who I work with do this when they blurb for others, and, based on the insight and the quality of the blurbs they receive for their work, the writers who provide them with quotes do the same.

They read the book and they don't just churn out boilerplate.

That being said, I'm glad your novel is getting great reviews and hope that it becomes a bestseller.