It's not even about plagiarism. But, sure, 1:1 or even 1:few instruction is great but even at elite schools is not really very practical. I went to what's considered a very good engineering school and classes with hundreds of students was pretty normal.
Ironically the practically of such instruction goes down as the status of the school goes up. I got a lot of 1:1 or 1:few time with my community college professors.