That probably was a joke, but in the case it wasn't: the whole purpose of listening to sound to your brain is to have a true objectively best audio experience, so there would probably only be identical technologies by different brands that sound objectively the best in everyone's perspective. If it didn't, it would defeat that purpose.
It was a half-joke, actually. I seriously doubt the technology would be implemented so cleanly as you envision. And I honestly think the situation would be similar to the headphone one we have now - all these different brands offering these different tunings, often at outrageous prices. So, I do believe ther'll be brain transmitters that transmit a more "flat" signal, those who transmit a bit more "bass" to your brain, or those who do something else. I know it would defeat the purpose of the tech, but the audio industry is still an industry, and when money talks, the purpose somehow often tends to get defeated.
I mean, look at all the freedom the Internet gives in everything. How to, then, explain the "This music/video is not available in your country" BS I have to look at every day that's at least 20 years outdated, yet is still here, and will be for the foreseeable future?
EDIT: And yeah, I think KZ will have the best brain transmitter's for the buck.