>>7159781485 year plans were partially responsible for the economic turmoil in the USSR and its satellite states. The state decides how much production is needed and then the bureaucrats have to make it work, that means if there is a surplus the production has to be destroyed or sabotaged, so as to not receive the same or higher quotas next time, and if it's insufficient you cheat, either on quality, or you cook the books.
In the case of the EU these 5 years plans often lead to regulations and bureaucratic involvement that end up sabotaging entire industries long term.