The hypothesis was not elaborated until 1979 when Brown and Witkowski put forth a proposal with 62 cognate sets and supposed sound correspondences between the two families.
They also published two articles proposing a "Mesoamerican Phylum" composed of Macro-Mayan and other language families of Mesoamerica.
In the late 1990s, Campbell (1997) expressed that he believed that Mayan would indeed some day prove to be related to Mixe–Zoquean and Totonacan, but that previous studies have not proven sufficient.
By transitivity, these two proposals would connect all three language families, rekindling the Macro-Mayan hypothesis as framed by McQuown.
Campbell (2024) considers the proposed connection between Mayan and Mixe-Zoquean to be likely, but doubts that the greater Macro-Mayan hypothesis is valid.