Does it really? Students in high school could easily take the lazy approach of believing that education doesn't matter because they will always have the basic income anyway. Noble people will better themselves under either system. Does a basic income system increase or decrease the number of people who aspire to better themselves?
I suppose it depends where you come from in terms of whether or not you believe the poor are mooching and lazy or simply disadvantaged.
Presented with the ability to continue education without needing to worry about putting food on the table, most people do in fact continue their education. Basic income is "basic" by nature. Very few will aspire to be a basic income earner for their lives. Even better though, even if they DO choose this path, they can choose otherwise at a later date and correct that mistake. That's the beauty of the system.