Yup, done all the time (and for a very long time) at some companies.
Different procedure for different operators, and yes, there is more than one way to skin a cat...but the concept that "it's been done all the time and for a very long time" has never been a valid justification for continuing to do so.
Aviators didn't wear parachutes or seatbelts in open cockpit aerobatic airplanes for some time. Didn't make it right. CRM was non-existant for a very long time. Didn't make it right. Many of the safety enhancements and practices we follow today, from avoiding landing under thunderstorms to fuel reserves to the use of automation came as the result of bloodshed and loff of property and lives. Simply because "that's the way it was done" doesn't mean that's the way we should keep doing it.
Yes, most of us have flown single pilot IFR a little or a lot, certainly with a MUCH higher workload than any of us have now in a multi-crewed cockpit. However, simply because we once did it all ourselves and could do so again in a pinch, doesn't mean we should.
I'm not new in the business myself...but I whole heartedly endorse standardization...including verbal callouts. I've no doubt based on my own experience that they save lives.