That statement requires quantitative and qualitative qualification. I know of people who are running sites with multimillion visits and revenue using a basic monolith. One even runs a Wordpress install configured with decent caching to serve millions of visits an hour.

If you are read heavy, offloading static assets to a CDN and having good caching will get you very far. If need be, you can load-balance between databases and you’ll still go very far.

Micro-services is not necessarily synonymous with scale.