ORIGINAL: TonyF
Retracts were really never about drag reduction. If some thought that was the case, it really wasn't. Now if you put doors on the gear and close up the holes, now you have drag reduction. But retracts were always about the look. They just make the plane look much better, particularly models of the era. Also a small improvement in bringing the weight of everything closer to the center of the model.
True it would be cleaner with gear doors, but take a strut and wheel and hang it out your car window at about 90 MPH. You’ll be amazed how much force it takes to hold that wheel in the slipstream.