Bitcoin isn't illegal in the EU so if I wanted to do something like OP (open my own mining farm) I could. Saying that you'll do it when it becomes widely accepted seems strange because by that time mining difficulty will be very high and there won;t be many coins left to mine. We also don't know what the price of electricity will be at that time and the cost of mining is going up every year. This would probably be the last thing on my mind in 10 years or so.
When it becomes globally accepted the price will probably be enormously high so the first thing I'll do is book myself a flight to some remote island, rent a cabin and read a book listening to crashing waves. I don't have any business in mind. I'd rather have some fun than start a business.
It is true that Bitcoin and other cryptocurrencies are not illegal in the EU, and you would be able to open your own mining farm if you wanted to. However, as you mentioned, there are several factors to consider before embarking on such a venture.
First, mining difficulty is likely to be very high in the future, which would make it more difficult and expensive to mine new coins. Additionally, the cost of electricity, which is a major component of the cost of mining, is also likely to increase over time.
You also mentioned that you would rather have fun than start a business. It's important to keep in mind that starting a mining farm is a significant undertaking that would require a significant investment of time and money. It's important to consider whether you have the resources and the desire to take on such a project.
You also pointed out that when Bitcoin becomes globally accepted the price will probably be very high, and you would like to book yourself a flight to some remote island and read a book listening to crashing waves. This is a personal decision and it's important to do what makes you happy.
Although personally I don't think Bitcoin reaches such a very high value as to make us all rich. Rather, I think that if we don't spend our Bitcoins, the price will hardly increase and mass adoption will take place.