Thought experiment: why is texting more popular than email?

I recently did business with a guy that uses email in essentially the same way most people use text.

We were working out the terms of a contract and it had the feel and immediacy of a typical text exchange.

I started thinking about how much better the tools are for email and how the two technologies essentially satisfy the same need.

What is it about texting that is superior to email?

Less spam. A higher expectation of immediacy. A much higher open and read rate.

But the tools for email are far more sophisticated.

What does it take to make the arguably superior technology capture the advantage that texting currently has?