Yes

When searching for a job is the best example. Though these are usually not hidden numbers and for me, if a mobile is calling it's either a wrong number or work related. Spam seems to always a landline.

Most people I know over 50 don't answer unknown numbers either.

But it's the same as spam... getting one victim out of a hundred thousand is probably enough to make it pay off.

Only when I'm on call.

Sure. Ever gotten a call from a delivery person with food? A doctor’s office with test results? A hair salon confirming an appointment? A teammate with an emergency at work? A taxi driver with the wallet you forgot? A distant relative that needs help? A potential customer referred by a friend?

My parents (over 70) get so many spam calls on their land line it’s comical. Last time I visited them the calls would come two or three per hour, nonstop, day and night. They would leave the phone off the hook at night so it wouldn’t disturb their sleep. It gets worse every decade. Answered a few of them and it was always the usual suspects: the IRS, Microsoft tech support, your credit card company, vacation winner, etc.

Best thing they ever did was cancel their (at least) 50 year old phone number.