I would not equate taking double-price lessons with famous teachers as "buying a trophy". Instead, this is a basic cornerstone of how all serious amateur and professional couples get their training -often from experts that they might be judged by once a year if at all. Its precisely those kinds of lessons where the key ideas needed to take dancing to a higher level of performance come from - the ideas that seem shocking or even outright wrong to those who've only seen these dancers on video, and never talked with or danced with them.
A number of times I've been given a very far-out and seemingly impractical idea by a local teacher, and just have not been able to make any sense of it or make it work. Then an opportunity comes up to work with the world-class expert who trained them. And then I find out what the local teacher was trying to say, but had not quite communicated accurately. The idea might still seem very challenging, but when tracked back to its source (or the nearest living thing to its source) you can start to see how you will eventually be able to incorporate it into your dancing to dramatic effect. Secondhand sometimes is just not enough.
But of course not every expensive lesson is worth the money. Unfortunately it takes some knowledge and experience to know who is and isn't worth the money. If you have more experienced friend without a financial stake in the opportunity, that can be a good recommendation for what is and isn't worth the money.