This is targeted hacking, when someone knows you have a lot of bitcoin (or own a valuable digital asset, i.e.
@John Twitter handle), they'll get your phone number, and use a number of social engineering attacks to the mobile company's call center agents to get to your account (i.e. baby crying in the background, husband John Smith on a plane for business travel, etc.)
Once they have swapped the SIM to their own phone, they target the email password reset, and since email is where the password reset for most online accounts are sent to, voila, access to Coinbase or Twitter, etc.
I've never been hacked. My phone is prepaid for over 10 years, you can port your number to a Google Voice number, $25 bucks. My cell phone is prepaid with a fake name, good luck to the hacker who finds out what my cell SIM number is trying to SIM swap that fake name (i.e Mike Hunt, or Han Jobs, could be steve jobs long lost cousin, lol), and use Authy (Google Authenticator clone that has cloud backup if you lose your phone) for 2FA even if Google Voice phone number is not susceptible to any of the text-vulnerabilities (i.e. SS7), still don't recommend it. Have a fake email and use VPN for crypto exchanges not tied to your real life. Don't use Facebook, linked in, instagram, all other social media, they are all tools by state actors to gather info from you and the hackers use them, too, when you post you're on vacation on FB, guess what, everyone knows and your auntie is a weak link to your security, she gets hacked, hacker has access to all your family network info, etc. I enjoy Twitter and Reddit, but fake names

All the info I just said are made up, only for entertainment purposes, you're welcome.