The universal education system we have today was never meant to "inspire learning" or anything similar. It was designed as a vaccine for illiteracy across a handful of subjects. I would argue it continues to deliver on that goal quite well (all things considered).
As someone who never attended, what Montessori offers is more the University-style inspiration and idea of learning for the sake of learning. This sounds amazing for the right people but I find it unlikely it could ever be universal.
Students who go to Montessori will have parent who believe in education in one way or another. The students will learn these values from their parents and so there's an inherent selection bias in the attendees and the positive outcomes.
However, education is not universally valued across our society. Public school exists for everyone to hit that minimum literacy bar.
What would be great is something like Montessori for every student who wants it. A different style of school universally available for the families that value it.