If it were only that easy.
I would love to just be a wholesaler. Life would have little stress...that is of course if it were easy.
I have only wholesaled 3 times in my career as I kept most properties to rehab. On occasion I would buy way too many houses in a short span and decide to wholesale one. I made 2k 9.3k and 24k. Why waste your time and add stress to your life if you can make 24k. I have tried to wholesale other properties I have purchased and no one wanted them so I was forced to rehab them myself. Some deals you just get lucky on that have huge spreads. Some are marginal.
To fully answer your question I would say it is possible to make a full time income doing wholesales. 60k-100k would definitely be possible if you had enough deals passing through your hands. You might on occasion hit a home run like I did but I wouldn't count on it happening too often.
There was a company here in Dallas that came out of no where and took over the wholesaling by storm. They were getting tons of houses under contract and had the cash to buy all of them. I guess they had huge backers. They also would sell the houses and finance them. It seemed to me that they had a great set up going and would often outbid me on houses. As you can imagine I hated them. I have no idea if they are still around as I am no longer on their email list. They probably made over a million a year wholesaling if I had to guess. They somehow had an amazing buyers list. Their buyers would pay more than what the house was listed on MLS for. I could never figure it out. It must have been that they offered financing.