I don't know why this is downvoted. Apples fall from trees, water is wet, and consulting businesses can be sold for money. Happens all the time.

Valuations are calculated very, very differently than for product businesses. There exist consultancies which have sold for amounts in excess of every YC company which has exited through today, although I don't know of any examples off the top of my head which rival Dropbox / Airbnb / etc.

But I'd you're doubting that e.g. you can sell a consultancy for $20 million or $200 million, you're doubting an observable feature of material reality.