Advocating that manufacturers should send swatches of known colour systems such as RAL to their factories sounds fine and dandy, but there's only one slight snag. They don't do it.
There are plenty of online colour converters (e.g. rgb to hex, RAL, CYMK, NCS, Pantone etc), so rgb is as good a colour language as another. Note though that RAL is a limited range, and the nearest r79 g45 b36 (for example) comes to is RAL 8016 'mahogany brown', which RAL describe as 'close but distinguishable'.
The issue of monitor variation is very valid, but the nub of the matter is that in terms of talking to each other, whether it is modellers here on a forum, or manufacturers trying to communicate with a factory, 'r79 g45 b36' provides a far better means for a more informed and objective discussion than "well, it's a sort of mahogany brown".