The non-advanced-educated feel marginalized because it will be ridiculously hard for them to get the education, and as things get more expensive their livelihood will go down relative to the elites.
The advanced-educated-but-not-good-enough will feel marginalized because they spent their time and money and got nothing in return, and now have debt and degraded livelihood compared to the elites.
When enough people feel marginalized AND something happens that weakens the state's power/influence, political instability will occur.
It compounds in US/Europe with regards to education, given that these two groups are politically opposite of each other, and advanced education is becoming a barrier of entry to upward mobility.
Turchin's 2016 book Ages of discord explains these ideas in detail.