I expect that AHP will eventually need to be replaced with something else anyway if they plan to extend the feature set in the future, since apparently they don't have the source code to AHP. They may not have the source code for the compiled firmware used in the Cypress MCU either. It may take significant effort to even reverse engineer the USB protocol used by the CM15A if they don't have the tech notes on that. It's possible that, for all these reasons, any change like using a new MCU may mean creating a completely new platform: new firmware, a new communication protocol, and new PC software on the PC side, completely from scratch. It may be too large an undertaking for the company to justify the investment at the present juncture. But we're talking about building and supporting an entire integrated platform.
On the other hand, I think that Dave Houston has a potentially great idea here. All that may be needed is to create a modded CM15A based around the Atmel MCU and provide a basic library for Arduino, put it out there, and see what happens. They wouldn't necessarily have to write much firmware; Arduino already has an OS that runs its basic hardware and has USB support. Authinx would need only write an Arduino library to control the PLC and RF hardware in the device. It would effectively be a new platform that is not compatible with the old USB protocol, AHP software, or SDK. But it may not even matter. Arduino is incredibly popular among hobbyists and there is quite a large open source community. The rest of the software will come.
It's not like Authinx will lose control of the X10 market by doing this. X10 patents are already expired and the PLC and RF protocols are already published on the Internet, so they've already lost control. Nameless Chinese companies with the proper resources can build knockoff X10 products, and they have. Any hobbyist with the technical skills and proper motivation and patience can build their own X10 hardware whenever they want, and they do. But it doesn't usually amount to anything in a commercial production run. Authinx already has a leg up here in that they have existing designs to work from, engineers on staff, a factory with tooling to build the products, shipping and marketing operations, etc., and they are positioned to build and sell superior hardware. As long as they continue to build quality hardware, people will keep coming back. If this catches on, it could help sell their other products and put money back into the company.