The claim of the thread is definitely true. RME products are expensive. The reason is lack of competition. Antelope, Motu, Focusrite, Apogee, UA etc. none can be as stable, low latency and easy to use on Windows like RME. On board DSP support is one of the disadvantages but with DAW and software plugin being so powerful today, it's not critical.
I am not a fan boy of any manufacturers though. I hope some Chinese audio companies can give some serious push here in pro audio like they did in many other fields. Or companies like Antelope can realize why they should treat old customers nicely.