are professional photographers just using their phones nowadays?

I've always thought Professional photographers used high-quality digital cameras and used their phones or tablets to process and store pictures further.

No

Hope that helps

No, professionals don't use their phones for photographs.

I'm sure if you looked hard and long enough you'd find photographers that only use their phones.  Phones may take good photos that look good on the small screen of the phone, but when enlarged just a little, the lens defects and the low-quality of the sensor (e.g. noise) become painfully obvious.  But image quality is just part of the equation.  A photographer needs to have control over the shutter, aperture, ISO, focusing, focal length, and many other aspects of the photo-making process.  Phones provide little to none of these controls.  Yes, some phones have 3 lenses, and many phones have exposure compensation.  But no phone has a variable aperture.  No phone has a telephoto lens for portraiture, sports or wildlife.

Bottom line:  If the phone allows you to get the shots they way you want and a file that can be used the way you want, then the phone is a good tool.  The problem is that nearly all photographers have many needs that simply can't be met by a phone.

Yes! Professional photographers use their phones all the time - to call and send text messages. To shoot? They use real cameras of course.

Some do, most don't. 

I very much doubt it.  Unless there’s some specific reason.  Mobile phones are not as good as dslr’s.