Businesses are valued based on discounted cash flows (DCF). If you're profitable and not growing, your cash flows are very stable & easy to evaluate -- you get a low P/E or P/E/G ratio. But if you're growing quickly with sane unit economics, most of the DCF value is in future years... which then results in much higher multiples relative to today's revenues & earnings.

Not the company, unless selling stock to raise cash.

Not the employees, if paid in cash instead of funny money.

Nobody needs that.

It's cultural.

People see other people’s wealth growing quicker because their investments grew more, increasing demand for higher growth investments.

Population growth inherently leads to economic growth assuming a sufficiently stable society and access to resources.

All of these create an environment where people expect certain ROI and make plans according to those ROI.