"I don’t doubt that there might be a few hotel executives that are willing to bet on this, and sign up at this very early stage at a discounted price, but contrary to the belief of many others, this is really unlikely, and it’s not worth spending too much effort on considering the expected return."

Not worth the expected return? This sounds like a case of you wanting 'instant gratification' and to be making huge amounts of money from the start, which is bogus. With a few customers you will:

1. Be getting the use cases, bugs, feedback directly from your customers

2. Show you can get some funding and are building something people will pay for (or if they drop you, you'll understand why)

3. Have numbers, knowledge, and customer referrals which will VASTLY help getting more customers. I.e. when you are in the sales pitch, saying "X hotels have been using this for a year, and have generated Y additional sales, and have learned Z metrics about their hotel guests" etc.