>>1649772This
You can ride pretty much any bike on gravel, of course there are arguments to be made in regards to best tyre width, tread type, flat or drop bars etc etc etc but all of that is down to personal preference and choices should be informed by the type of terrain the bike is to be used on and the aims of the individual rider.
Of course the industry just loves a target market, to be fair to the industry there was something of a vacuum in the area that sits between road specific sports cycling and technical mountain biking, although as /n/ well knows there never was such a vacuum in reality as pretty much any 1980's/1990's rigid mtb is pretty much ideally suited to so called gravel biking because gravel biking is just 80's/90's era mountain biking rebranded for the consoomer.