Although ARCA company has been established for quite some time, it can be said to have a peculiar style, belonging to the oddballs among many private aerospace companies.
Dr. Freeman was not wrong about their playful nature; this company never painted pie-in-the-sky promises to lure investor funds, nor has it developed commercial projects. Instead, they like to dabble in unorthodox stuff.
Besides the projects funded by NACA last century, they are probably the only ones who have also invested considerable effort to research the aerospike engine, and later they even came up with the heretical water engine.
As for why they were targeted by NACA and pushed Pratt & Whitney to acquire them, the reason goes back to the CZ-18.
Before it became official, NACA had already formally confirmed that XAP had truly initiated the project and made substantial progress, which then caught John's utmost attention.