A deli said to be making $35,000 in sales in said to be worth $100 million in the stock market. How does something like this happen?

It doesn't.  That sort of income could not possibly put any company on any stock market.

It is speculation.

This is brought to an extreme with large corporation like Apple for instance: $2.27 TRILLION market capitalisation, while sales are $274 billion, net income $57 billion, assets $324 billion and equity barely $65 billion. Why would someone pay $2270 for something that is worth only $65?

But  going even beyond that is something like the bitcoin. Bitcoin does not have ANY asset, its value is ENTIRELY determined by how much someone else's willingness to  pay $55200 to get one.

35k a day... Blood sweat and tears.. Try it sometime