just to mention, to me as someone who has toured for a long time, fully loaded means fully loaded, and these bikes certainly arent marketed as this, but specifically as for want of a better term, the "bikepacking" setup--which generally means less stuff and certainly less stuff up front, weight wise.
it certainly makes sense, as you said, equipment is generally lighter nowadays, tents and whatnot, so it certainly is a lot easier to have more comfort with a lot less stuff than lets say 30 years ago when I started.
I reckon just about any bike can easily handle the more or less amount you mention, and given these bikes are made with the intention of going on rough roads, they'll be fine.
My wife and I have done "fully loaded touring" on our tandem, 42 lbs. of gear total, including all the bike tools, pumps, bottles, bags, all that stuff. Very comfortable rain or shine, good times, though we were only out for a few weeks at a time. Our non-bike gear is the same stuff we use for long distance backpacking. We do take only minimal civvies, just enough to hike, eat out, explore towns, etc. So 50 lbs. apiece is a heckuva lot of gear. That's more than we take on a 10-day backpack including food and water.