Not really anything new, at least not for kids coming out of highly ranked magnet public high schools.
OVER a decade ago, my kid’s public HS (ranked top public HS in the country by WSj, so not necessarily a “typical” HS) required all recommendation letter requests be submitted to the teacher by March of Junior year.
The kids applying to T20s (virtually the entire class, LOL) had also completed all standardized testing (except for any senior year AP exams, of course) by the end of Junior year
The first semester of Junior year english class was the “write your college essays” term.
I think everyone else is just catching on to what was happening for a long time at some schools.