I got sidetracked and forgot to respond to the initial topic..... Through my long life I have used Brownie cameras, point-and-shoot cameras, Polaroid cameras, and 35mm SLRS when it comes to film. My introduction to digital photography was with the Nikon Coolpix 900, a delightful P&S that did amazing things in a new and different way from my film experience. I went through a series of Coolpixes for a while and the SLR and lenses pretty much spent a lot of time on the shelf as I was having fun with the digital cameras that didn't require being processed by a film lab and had this neat little card that I could take out of the camera and stick into my computer and look at my images right then.....
Eventually, though, I hit the wall with the Coolpix when one day I was out shooting and trying to get the camera to do what I could easily do with my SLR-- and that was the day I realized that it was time to move on to a DSLR, Nikon's D70. Bought the D70 and once again my SLR and lenses remained on the shelf as I bought new lenses and happily got back into the kind of shooting that I most loved, and re-experienced the joy of being able to control the camera and the lens in order to achieve the kinds of images I wanted. Went through a series of DSLRs then as Nikon kept bringing out newer versions of the bodies and added more to their lineup of bodies and lenses....
My introduction to mirrorless came when a friend came over one day and brought his new Sony NEX 7. It was the first time I'd ever handled a mirrorless camera and the first time I'd looked through an EVF. He talked excitedly about something he called some strange name that I couldn't quite decipher and how it helped with manual focusing when one wanted to use that (later on when doing a Google search I finally realized that he was talking about Focus Peaking). I was fascinated by that smaller, lighter weight NEX 7 and its lenses, and sure enough, soon I had one of my own.
Time went on and I ebbed-and-flowed when it came to photography, at times not picking up a camera for weeks. When I did it was usually the NEX 7 or the small RX100 camera with a 1" sensor that I'd picked up to use for travel. Things began to shift when I purchased the RX10 IV "bridge" camera for a specific trip because it ticked all the boxes I'd need for that trip and I figured it might be nice to use once in a while around home, too.....
That camera, which I still have and still use often, is the one which finally got me back into photography in a more active way -- that, and the POTD thread right here at MR. I started out by posting a few images from my archives but then found myself wanting to share new, fresh images and soon I was shooting on a frequent, nearly daily, basis. Eventually I wanted to do the kind of shooting that I most love -- macros and closeups -- and while one can do closeups with the RX10 IV, it's not the same as shooting with an interchangeable lens camera where one can easily swap out to the right lens for the job. I wanted to be using a real macro lens again.
So, fine, I had a bagful of lenses in the other room and the camera bodies to which they could be attached, but by this time I had been thoroughly spoiled by that EVF and the whole mirrorless camera thing. My NEX 7 was getting long in the tooth and I began to realize that I was ready to make a change from DSLR to mirrorless and to buy some new gear -- but what to buy? This whole process took a long time, as I began wrestling with different possibilities and watching the camera market to see what was coming along and what was already available out there.
The day I brought home my new mirrorless A7R IV, I had two macro lenses in the bag with it and a medium-long fast telephoto for starters..... The first time I put that 90mm macro lens on the camera and shot a closeup and adjusted my settings and shot another one, I knew I was HOME......
No, everyone does not need a DSLR. I don't need a DSLR any more, either. I loved them when I had them and used them but for me that time has passed. For me the present and the future lies in mirrorless and I am more than happy when I have a lens on the camera that is suited to whatever it is I'm about to shoot, and I spend some time in experimenting with various settings, and then in swapping out lenses if along the way I have an idea of another approach to the subject, and then reviewing everything in the computer and tweaking things here-and-there as needed (which it is when one shoots in RAW).
Over time I have added more and different lenses for different types of shooting with my A7R IV and I have different types of cameras for specific purposes as well -- travel in particular. I shoot pretty frequently -- often every day, actually -- and I love being able to pick up the right gear for the ideas I have in mind and to get the kinds of images I most love.