Your parent stated clearly "But until then they're, by contract, obliged to offer their guests only their contract partners awfully slow internet."
So it's in the terms.
I considered replying to that comment stating how I would write the telco's legal department to get them to release this provision but to be honest given the way lawyers feel they need to represent their companies the answer would probably be, "no."
I would say words to the effect of: 'this is a historical provision from a time when it was unclear what pace the Internet would be adopted, by buying into such a long contract early, we supplied (telco) with much-needed sales commitment which thanks to early adopters like us is part of why your company (telco) was able to take an early lead in deploying out (infrastructure). At that time nobody could have guessed the speed with which infrastructure would be deployed, and unfortunately the speed we have contractually bought into no longer serves our customers. For some context, visiting executives have actually resorted to visiting the reception area of the fleabag inn down the street, where they even have hostel "dorm-style" rooms (6 beds to a room), and probably pay around $79.95/month for their 100 megabit package simply due to how late they were able to deploy. This reflects very poorly on us, and we have had to make various excuses, but of course never giving (telco's) name, as the guests might not have all of the above context. As we are materially affected in our business by some of these experiences, however, we have had to review our possibilities. We believe in the contract with (telco) and agree that its financial terms are valid, made sense at the time, and we are happy to honor it until its expiration. However, one clause in particular prevents us from pursuing unrelated mitigation. A good technical solution would be to offer a parallel, current solution, while continuing to pay the full terms of our contract with you. What is preventing us is, specifically, clause 7.6 of the attached contract, that states we are obliged not to offer a parallel service to our guests. We'd like your permission to be relieved of this requirement, as it is becoming an unconscionable burden, but does not impact you financially in any way. I am sure you agree that (telco) would not pursue legal action for doing the absolute minimum we can to service business customers, and in fact as we agree with and understand our contract we are happy to continue to make payments on it during the full term. We would simply like to be able to augment the level of service we had agreed, which no longer lets us compete effectively, and seek your permission to do so whilst honoring the full payment and other terms of our contract with you. Thank you for your attention."
To be honest I couldn't think of a way to do that so that a corporate lawyer would say, "sure." Well, the above is worth a shot anyway.