Honestly, most of the incentives aren't aligned with breaking them up or trying to lower prices. If the large corporate entities were broken up, they wouldn't have the scale to compete against their much larger American counterparts. They'd either get pushed out or bought up. And low prices aren't the goal for a company that is protected by government policies - they'll aim to maximize profits within the policy framework instead, and the framework itself does the job of preventing competition from smaller upstart rivals.
Think of the Canadian aircraft manufacturer Bombardier. Canada wants to keep a domestic aircraft manufacturer around so they have a backup in case of US shenanigans (like what just happened with the F-35) so the government ensures there's ongoing contracts for those domestic aircraft as well as subsidies for things like manufacturing plant expansion or modernization. But Canada's population only needs so many aircraft, so why would they waste government resources on a new upstart rival aircraft manufacturer? Bombardier knows this too, so why would they spend their own resources on R&D or modernization when they know they can get the government to pay for it instead? It's a feedback loop, and not necessarily a good one.
Think of the Canadian aircraft manufacturer Bombardier. Canada wants to keep a domestic aircraft manufacturer around so they have a backup in case of US shenanigans (like what just happened with the F-35) so the government ensures there's ongoing contracts for those domestic aircraft as well as subsidies for things like manufacturing plant expansion or modernization. But Canada's population only needs so many aircraft, so why would they waste government resources on a new upstart rival aircraft manufacturer? Bombardier knows this too, so why would they spend their own resources on R&D or modernization when they know they can get the government to pay for it instead? It's a feedback loop, and not necessarily a good one.