Pointless argument unless you define what startup means.

Different dictionaries provide different definitions.

A common one is that it's small and recently started business, but it's a very vague boundary.

Half a trillion dollars isn't "small" no matter how vague you want to make the boundary.

Neither a billion isn't small no matter how vague you want to make it, yet, we label startups with this valuation as unicorns. So where is the boundary? 10 billions? 100? 1000?