Go back to 1999 and build a website supporting a million concurrent users. How much hardware do you need? What are your fixed costs? What are your engineering costs? How do you even market your thing?
The hardware cost is low, as is the barrier to entrance. And the users' expectation is higher.
To attract today's users, you still have to be better than your competitor's website. The fact you can easily build a website for millions doesn't mean it will actually see millions of visitors.
Go back to 1999 and build a website supporting a million concurrent users. How much hardware do you need? What are your fixed costs? What are your engineering costs? How do you even market your thing?
Now do the same today.
What's different?