so the only way to grow a business is to sell to people who tolerate spam and avoid those who don't?

They complain a lot less.

This is why B2B is easier than B2C.

A consumer will pay $10/mo and ask for the moon. Threaten to leave. Get angry at an email.

A business will drop $10k no questions asked and your product can be garbage. As long as it solves or attempts to solve a pain point. Emails won't be seen as spam. Except by ICs/eng, perhaps.