Education around the world remains expensive and broken - there are a billion things why it shouldn't operate in the way that it does. Assuming that the biggest reason why education can't be more accessible is because of the required human-power required, there might be a way to fix this issue.
In my high school, for our co-curricular activities (clubs, sports etc), even though most clubs had 100s of students, they were managed by just a handful of teachers (usually 2-3). The ratios that this would hit is beyond the ratios that would be sustainable in the traditional classroom setting to promote conducive learning (I think massive lecture halls are a garbage way to learn, I barely attended any of such lectures in college, and always opted for smaller classes if there were an option). The reason this was possible was because there was a huge dependence on student leaders within the clubs.
Our high school was 4 years, so the system worked where when you first joined, you'd be guided and trained by the Year 3s, and when you went to year 2, you'd be guided and trained by the Year 4s. Then when you progressed to year 3, most of your learning was self-directed (with some form of leader guiding this within your own year), but also heavily focused on improving your basics through coaching and guiding the year 1s. And as year 4s, you would be leading year 2s and setting overall direction for the entire club. In this scenario, everyone gets essentially closely partnered with a "mentor" (or student leader) to learn from so individualized learning is still retained.
This system takes off a ton of pressure from "teachers" to manage the club, through hyper-delegation and hyper-scaling.
This concept can be the core for building a hyper-scalable schooling system, rather than the current systems that either fall into a bucket of small classes with individualized learning, or massive lecture halls. This would be an awesome system to ensure that even as students progress through the grades, they would be able to retain information and enhance it through teaching (since teaching concepts is an awesome way to learn even more as it exposes you to the parts you aren't as confident about). It also teaches students, from the start, very important skills like how to self-learn, how to plan to teach, how to organize and how to lead. It also builds very strong community (as you can imagine), acting as a strong support system for both personal and professional aspects.
This could grow into something massive, covering K-12 as well as tertiary education, being open sourced across the world so that anyone would be able to copy the model and implement in their own sub communities. The goal of this is to lay out the infrastructure and prove this model so that it can grow anywhere and everywhere as long as someone takes lead to initiate it (which hopefully would be a lot easier with the open sourced resources we'd gather and document). This would primarily be a non-profit initiative. To make sustainable, it could be tied to an education model as seen in:
YC for MicroSaas
Obviously, this is a huge effort. I do plan on working on this once I feel like I have secured enough $ personally to not have to worry about it, and till then, I look to continue slowly planning it out and getting there.
I'd love to partner with someone who's passionate about and has experience in education. There's ways this can be made simpler with tech as well, but that doesn't need to be the core aspect.