In the late 20th century, Turkey was an EU entrant candidate, and looked in better shape on the democratic, corruption-reduction and economic criteria than some other candidates. Then, of course, Erdogan happened, and that was the end of that. But, pre-Erdogan, "Turkey will join the EU and see the same sort of rapid progress other EU entrant states have" wasn't a ridiculous idea.

The EU can be a relatively effective machine for rapidly dragging countries forward, though a certain amount of cooperation is required.

> The change you need for them to be at the level of Europe is cultural and that takes many generations.

Some of the former Soviet and Warsaw Pact states have seen extremely rapid change and progress under the EU, particularly on democratisation and corruption reduction. Others, not so much; the EU can lead a horse to water, but it has difficulty making it drink if it doesn't want to (notably see Hungary). But you're certainly not talking _multiple generations_.