There are, lots of em, but they aren't as good. LEGO charges a premium, but their manufacturing precision really is phenomenal. Also, LEGO's premium isn't that extreme. Their sets have worked out to about 0.10 USD per piece for decades, they've just gotten bigger and more elaborate.
The other brands also don't have the same brand deals, I can't get an X-Wing set from Mega Bloks, for example. Though notably you can only get Pokemon sets from Nanoblock, and the experience of assembling one will make you appreciate the work LEGO puts into their instructions and manufacturing precision.
This is true. My kids and I have sets from all various brands, including some Lego compatible (knockoffs) directly from China. Only the the true LEGO brand blocks have precision in every block. Their sets are the most satisfying when clicking together.
The other brands also don't have the same brand deals, I can't get an X-Wing set from Mega Bloks, for example. Though notably you can only get Pokemon sets from Nanoblock, and the experience of assembling one will make you appreciate the work LEGO puts into their instructions and manufacturing precision.