[shalmanese]

Lego found itself increasingly unable to compete on quality as its competitors became good enough so Lego pivoted instead into building a defensible moat around licensed IP. Anyone can create a "Wizards and Warriors Brick Set" but only Lego can create the "Harry Potter Hogwarts Lego Set".

[Cthulhu_]

It pulled them out of a rut as well; if they hadn't done the IP's, the multi-media projects (like Ninjago, Nexo Knights, etc), the collector's items etc, the competitors would likely have taken up a lot of their market space once their patents expired.

That said, lego has (IIRC) always had really good quality and precision.