Possible, although unlikely. The -CDM model does an astonishingly good job of modeling the observed universe. But, that doesn't mean it is right.
In the case of aether, people didn't stop investigating it until a) experiments that should have observed no matter what saw no evidence of it and b) another theory that agreed with this new data came along.
People who trot out the tired old "dark matter is just like aether!" line typically do so while patting themselves on the back for their cleverness, while neglecting the above.
If there isn't WIMP dark matter, or even isn't dark matter at all, then we'll find out. That's how science works.