I just have traditional units on all lines so I pay x per line plus £3.90 * 2 per month for traffic. And I get more than I can use because it is only £3.90 per TB [!] overnight. So I do massive downloads overnight, four hour downloads flat out and then have stuff to use offline in the day.
I could not give guests ADSL, do not have the bandwidth to spare. And just like you say, would end up with people moaning like the Waldorf Salad, and bad reviews etc because it is not free and not 50Mbps per users. I could resell 4G, or just tell them to use 4G, even give them a free SIM if they don't have one (foreign sim, wrong network - Vodafone definitely useless also O2 poss for some reason). But the latter option would mean that I don't make any profit from it. and have the admin. And free SIMs see, to be more difficult to get hold of these days for some reason. I have stayed in hotels where they charge you x per day or even per hour and no usage metering. But i think guests in hotels like free internet. If I stay at the Savoy in London, I wonder if there is free internet, maybe 1 Gbps per guest and 802.1ac wave 2 would be nice.
Saying we have no internet to offer, is part of the remoteness myth romantic off the grid thing and you have excellent 4G anyway. But in the future some people may be Waldorf Salads, and we are fresh out of waldorfs.
If I pay for FTTP ethernet at £100k, then I need the guest to repay me. and they won't can't and there are not enough of them. But that is what they will expect.