[tialaramex]

> What I do know is that in the EU you have to enforce your trademark so that it does not get a commodity.

When I say "myth" I mean, very specifically, that many people like you "know" this falsehood. What you're doing here is just underscoring how widespread the myth is.

"But I really believe it" doesn't stop it being a myth, neither does "But lots of people I know believe it". In fact if nobody believed it then it wouldn't be a myth - for example "Cheese is made exclusively by alligators from the tears of French Kings" isn't a myth because nobody believes that.

You can end up triggering Estoppel or Laches if you are sufficiently lax in enforcement, but your rights don't magically dissolve if you choose not to sue everybody who might be argued to use your mark. Nike could (and in the past have for similar works) just ignored this infringement.

Lego's big problem in Europe is that they would prefer if they were the only people who get to make building blocks, if other building blocks have to be needlessly incompatible then everybody will buy Lego, but if compatible blocks are allowed (which the EU says they must be) then you can just buy "real" Lego for Luke Skywalker and a Snowspeeder and then use cheap compatible Chinese blocks with your local store's brand for the white blocky Hoth landscape. That cuts into Lego profits. Too bad. But the cheap Chinese block makers don't pretend what they're making is "Lego" it doesn't have the Lego logo, it just fits together nicely.

[ibotty]

Sorry, you are wrong. It's not about compatibility. It really is about other brands being able to say "LEGO blocks" on the box in the shop and people posting youtube videos with LEGO in the title but using other brands.