The changes that are being introduced in laravel are more complex than what it was intended, also there are some breaking changes, so it made sense to Taylor to bump it to 5 instead of 4.3.
The videos should still work, when creating the project just run
$ composer create-project laravel/laravel my-project dev-develop
Since I'm using "dev-develop" and not a version number, nothing really changes, except your knowledge that instead of 4.3 is 5.
EDIT: Sorry, I meant "dev-develop", updated