I have heard this, but not really seen it happen IRL TBH. Yes, the classes are smaller. The teaching quality may or may not be good - same as other colleges. One major difference is that some professors at smaller colleges have frank talks with pre-med wannabes who aren’t up to the caliber of others and kindly suggest other paths that could be right for them. At larger class colleges, it’s either kids figuring this out themselves or the pre-med advising that does it.
I also don’t suggest keeping the fact that one is pre-med to themselves. I suppose it’s a good route for the person who likes to stay private with their life, but it REALLY cuts down the camaraderie formed with many students at colleges - the “we’re all in this together” type of fun they have with study groups and sharing what they’ve had in opportunities, etc. That’s just as much part of the fun college experience (for many) as any other thing. I’d hate to see students missing out feeling they have to be secretive to be successful - 'taint so. Many in groups celebrate with each other as they get their acceptances, etc, and still stay friends even with those who end up on a different path.