Lego has more sets today that are just bricks or bricks with multiple models than they've had for like 35+ years. Not to mention dozens of books they put out with other ideas.
And I'm not talking about instructions for how to build a different set, I mean "Here's a way you can combine these pieces that you might not have though of - figure out what to do with that" or "You like animals? Here's how to make a tail. Go make some animals."
My daughter gets plenty of small sets, and then typically just wants to dive into all of the extra pieces and build something completely different. Sometimes these are inspired by Lego suggestions. Sometimes they are crazy things she comes up with on her own.
There is nothing that Lego sells that legitimately limits people in what they can build.