Sharing my 2 cents here. Well, there are multiple reasons for edtech failing but I think it is mostly about the basics.
What problem are organisation like Byju's solving? Is the problem " Quality education is limited to metro cities. So, Byju's should use edtech format to reach out to masses" or " Byju's curriculum is superior than that of school and college. So kids need to depend on us instead of schools" or something else?
If edtech want to be the preferred education medium then are they saying entire Indian academia like schools and colleges are no longer required or do Byju's see themselves as a supporting entity to regular academia?
While the actual users may be kids but target customer are their parents. And these are the parents who have received traditional schooling. They will never accept Byju's etc. as an alternative to traditional schooling.
So I think the reason for failing edtech is their lack of clarity on what they want to be. I think Udemy is case in point. They are clear that they see themselves as a supporting function for corporate employees, B2B business. They are doing pretty well for themselves.