Then it had better be really urgent unless you're one of a handful of people. Even as an older person, I mostly ignore phone calls if I don't recognize the caller ID--and, even then, unless it's a call I know I want to take for whatever reason.
ADDED: Where I work, chat is a more time sensitive than email but basically no one phones out of the blue.
Focus mode is better because you do not get distracted at all by the ping. This allows people to send you a message at any time and you will see it at some regular interval. I'm fine checking messages once an hour but currently they come in at random times regularly. One 10 message ping is much less distracting than 10 pings.
I would much rather someone press a button to say "This is very important, send it now" over calling me where I have to scramble to turn off my music, put my headphones on, etc before answering.
Text messaging is asynchronous communication, if someone is expecting an immediate response, they should be calling.