the most concerning limitation of buying e-books

I may continue to buy e-books, because e-versions are cheaper, but I'm constantly aware of a danger. When I buy an e-book from a for-profit source, I don't actually own the book. It's on the company's server and I only bought the right to read it. In this era of government and corporate censorship, it's always possible the company might decide that customers should not read that book, and remove it from their server.

I'm also aware that the popularity of e-books is one of the various reasons why paper books are now increasingly expensive; and that by buying for-profit e-books, I'm perpetuating the cycle.