"Possible", in that it cannot be categorically ruled out over scenarios and timescales, sure.

But a lack of "net neutrality" isn't going to cause broadband providers to magically freeze their prices either. So it's a choice between a one time "possibly more expensive", and continual raising every time providers buy more advanced dpi gear, segment offerings into more proprietarily-priced "services", and slowly dismantle the end-to-end principle.