Why are domestic toys that copy Lego and are anti-Lego not sued? Doesn’t LEGO protect its intellectual property rights?

In fact, everyone who deals with intellectual property rights knows that even if you apply for intellectual property rights, there will still be a lot of counterfeiting. The cost for everyone to seek compensation is too high. Intellectual property rights are mainly self-protection. If you apply, at least if you do well, you won't be afraid of someone maliciously registering your application, and then you will be compensated, or they will make you suffer a big loss by letting the water go to fish. This is the most important effect!