This is very true, although the Foveon was superior in resolution and lack of color moire only
Foveon is only superior in resolution if the number of output pixels is the same. But if you count photosites, i.e. 3 per pixel in a Foveon, then Bayer wins. A Foveon has about the same resolution as a Bayer with twice the pixel count, but the Foveon has three times the number of photosites.
But the problem is colors.
Foveon has a theoretical minimum color error of 6%. Color filter sensors (eg. Bayer) have a theoretical minimum error of 0%. Color filter sensors can use organic filters that are close to the filters used by the human eye. Foveon is based on the filtering effect of metals. In addition, there is significant overlap between the sensitivities of the three layers (a red photon may excite any of the three layers, for example). This leads to metamerism, where two colors perceived the same to the human eye will look like two different colors to a Foveon, or vice versa. Good luck matching makeup to clothes for a fashion shoot.
In addition, the Foveon has horrible effects when colors clip. If you shoot a bright red flower and the red is overexposed, it will "blow out". On a Bayer sensor this looks like a very red flower. The detail might be gone and it's not pretty, but it's red. On a Foveon it turns grey. The image processor tries to fix this, but even that's a recent advancement.
The sad thing about the Foveon is that it would make a great video sensor. It has good on-chip binning and could do live-view or movies long before anyone else could. Sigma threw away this competitive advantage.