I think what might be confusing a lot of people is that early on when Malwarebytes first changed over to the yearly subscription model rather than the lifetime license model, they did only offer 1 license for 3 devices (though it was for a yearly fee, obviously, not lifetime) and this was the first time Malwarebytes offered anything other than single device licenses for consumers (business licensing was always handled differently and was always based on yearly subscriptions from the start) and I believe that may be what many users are remembering either that, or some unscrupulous sellers pushing fake licenses/cracks etc.

They weren't competing with big AVs back then because they always marketed themselves as a complementary solution to be run alongside an active antivirus/IS solution (the layered approach to security) and only began marketing Malwarebytes as an AV replacement with the launch of Malwarebytes 3, and by then they had already gone to a yearly subscription.

I've been hanging around these forums since before Malwarebytes Anti-Malware even existed (back when the only product they had was RogueRemover) and I was around through the first betas for the original Malwarebytes' Anti-Malware product and actually started working for Malwarebytes as their first QA and eventually became their first Product Manager (I was in charge of all products, including Malwarebytes' Anti-Malware) and I know for a fact that it was always 1 device per license for Malwarebytes' Anti-Malware Pro lifetime licenses.

Malware premium