None of this changes the fact the we have a limited number of supplies on this planet (and we've somehow let corporations start buying exclusive rights to fresh water supplies), but if you think you are properly equipped to build a floating ocean fortress or a cave-lair deep under someone else's property, feel free to try.
Why are you assuming that people can not group together and pool their wealth and resources? Almost no one starts a business with just their own savings any more.
What if someone already bought up all the resources and sells them to those pools of people at super-outrageous prices that prevent them from properly starting a business? Total control of an asset prevents competition, and just assuming "someone will invent something better!" does not work for all cases.
Life isn't an Ayn Rand novel
You're making the same mistape I pointed out in my OP. Take total control of an asset, someone else will create a substitute. Or people will substitute nothing for the assets, and the business will lose money until they lower the price.