It's very common, when designing a solution, to have specific requirements that are not solved by existent products, or the choices available are not cost effective. For that reason, having a hardware designed or adapted for specific project can be a better option.
The costs of developing a proprietary solution was also prohibitive not long ago. Currently, with plenty of circuit board manufacturers, easy access to off-shore services and 3D printing, costs is not a barrier anymore. With small investment it's possible to design a full platform, or expand an existent solution to do exactly what it's required.