I can't imagine Saylor's ambition to become the world's largest BTC holder. He's on track to reach 1 million BTC, and I'm sure he has many ways to secure new capital injections.
Let's clarify this because of the novice.
Michael Saylor is a person, and MicroStrategy is a company. Saylor owns roughly 17,732 BTC as of today, while MicroStrategy, the company he's the executive chairman of, has bought over 600,000 BTC. Meaning that it's MicroStrategy that has over 600,000 BTC to its name, and of course, it is owned by many investors.