When I was younger, I could've easily sat on a bike for three hours at a clip
When I was younger I did Innsbruck in Austria to Ostend on the Belgian coast stopping only for Fuel. I simply wanted to go home (I had brief kip on the ferry) as the weather was seriously lousy that year. I had a tank bag with some fruit and sandwiches in - and ate riding (want to amuse drivers - apply throttle lock and peel a banana at 80mph). Doing about 80mph and getting about 240miles before HAVING to stop. So yes 3 hours. And the run from Dover to my parents was always non stop - 185miles. Not as fast but longer (almost 4 hours) - it was no big deal back then, for us anyway. We all did it.
My parents live on the south coast of the UK but all our family stems from the Manchester area. I don't think we ever considered it would be odd to do that run non stop. Generally did. Even my dad and he was NOT a "driver".
I know "I" could not do more than about 800kmh a day now before my brain gets weary. This also is pretty much the tank limit of both our cars. My wife insists on a stop after 350-400kms.
I'd really like to be able to get to the coast from Madrid non-stop though. I'm not doing the runs for fun - they're transit runs to catch ferries (so there is a time element) and I switch chip mentally.
On my own I use the bike as the ferry is then MUCH cheaper. 450kms to the ferry and I could and would do that happily. I've made sure the R3 is comfy to do so. On a stock seat - it would NOT (imo) be possible.
So If I do add capacity it will be addon.
The bugger (for me) is that the smoothest and fastest (and reliably traffic free) run to the ferry has some gorgeous picturesque sections it would be fine to stop in (in the car I have) - but NO fuel. It's a TRUCK route - they have big fuel tanks so there's no commercial incentive to have fuel stops. And for most cars it's no requirement either. There are a couple of these truck routes that are really wonderful roads - deliberately built to allow long distance traffic to avoid local traffic - often long sweeping bends through rolling countryside - to keep it interesting. But there is a reason why almost nothing except trucks use them - Yup - no fuel stops. Lot's of "pull off" areas with loo's, showers and peace and quiet to sleep if required - but no fuel (or food). There's always clean drinking water.
A few years ago we came across a Dutch BMW GS rider stood next to his bike - whilst his girlfriend went went with the Guardia Civil to get fuel. We were in the car - and only avoided joining them as my wife had INSISTED we fill up in an a town we stopped to visit. 200km road - NO fuel. He was really quite shocked (tbh so was I). It's partly why the RotoPack fuel cans have gained popularity in Europe - get down in to some places like Serbia and you'd better have a reserve supply - because sometimes the fuel stops are dry.
Simple "fun rides" are something else - they're not about expediency. They're supposed to be relaxing - and for many also social. But for those runs I'd honestly rather use a different bike. When I was younger - 500cc sports bikes (especially Laverda Montjuics). Now a "Classic" bike. Here anyway you'll attract more interest with a Classic than "the monster" from non bikers. Old guys who'll come and say "wow I remember those".
I've never ridden in the US - as my trips were generally business and we were given hire cars - but I can think of drives we did up in New England where fuel stops seemed scarce. They were probably just around a corner - but when you don't know - that's intimidating when the low fuel light flashes. Now imagine doing it in a country where you cannot communicate. I'm fully trilingual and can use two more - but I've been to Eastern Europe within the EU and NEEDED a translator.
Nobody has to do 2 hours if they don't want to. But acknowledge some of us HAVE TO.
Hell I have a friend who is a member of a VESPA club. They do 600-700km days which on a VESPA is a looooooooooong day. He also did Madrid to the VW factory in Northern Germany non stop in a 1960's Beetle last year. They arrived late and the factory museum was shut. Thay were tight on days leave - so they simly drove back - Now that I admit is pushing the boundaries.