Not really an answer to your question, but one partial solution to the problem of having your number leaked or sold is to setup a service like Twilio to act like a phone proxy. You can have Twilio forward calls it receives on a different number ("spam number") to your actual phone number ("real number"). You provide spam number to anyone who isn't a business or personal contact. Every few months, you rotate spam number. If your spam number is leaked, you don't care because its only a transient number which isn't more permanently associated with you.

You can also have more permanent proxy numbers for services or people that may need to get in touch with you long term.