I don't agree at all that flipping is over for now. In fact, I see the right flips (location, materials, etc) as the houses that are going quickly as opposed to owner occupied homes that need lots of work. Buyers don't want to do a lot of work these days. So savvy flippers can buy a house, get it on par with buyers' expectations and ma a bit of profit for their "sweat equity". Now, it is true that flippers should not expect to buy a house, slap a little paint on and charge a huge mark-up.
Also, it is true that when a Realtor offers to help with a referral, they will likely get a referral fee from the referred agent. However, buyers do not pay their buyer's agent a commission, so the referred agent would have no ability to negotiate a commission with the buyer. The referred agent is paid whatever commission the listing agent offers on the house the buyer selects. The referred agent would just then share a small percentage of that set commission with the agent who gave the referral. Now, when the flipper has done the work and then chooses to list the house with the Realtor they were referred to, they then have the ability to negotiate a listing commission and the original agent who gave the referral is no longer due a referral fee. So in a nutshell, a referral in this situation does not limit a consumer's ability to negotiate with the other agent.