Can You Still Bootstrap a Unicorn in 2025?

MailChimp famously bootstrapped their way to a $12B acquisition without ever taking VC money, which feels like the ultimate founder dream. But is that path even realistic anymore? Today's unicorns seem to require massive compute infrastructure, Al/ML capabilities, and enormous data science teams just to compete. Even simple products now need sophisticated recommendation engines, LLMs, or complex cloud architectures that burn through cash. Sure, you can still build profitable bootstrapped businesses, but can you realistically get to unicorn status ($1B+ valuation) without institutional funding in 2025? Or has the barrier to entry gotten so high in terms of technical complexity and capital requirements that it's impossible now?