Bill Ruger didn't get to rewrite history just because his fan boys believed him...
Please post links to your other works of fiction. Entertaining reading for the non-gun person.
As already posted, the GP-100 was introduced for three reasons. First, because it required less handwork than the Security-Six, therefore less expensive to produce. "Just raise the price" of the Security-Six is not an answer in a competitive market, when Ruger could introduce a new model that cost less to produce.
Second, the GP-100 was also less costly to repair when required. All heavy-use DA revolvers eventually need repair, whether the owner recognizes the condition or not. Since you seem overly enamored of S&W, they required repair far more often than any Security-Six. I'm a factory-trained S&W Revolver Armorer, and the "good ole days" of hand-fitted S&W revolvers resulted in guns that required a great deal of hand-fitting by skilled technicians to repair. It wasn't until the redesign/MIM era that S&W finally got to the point of parts with consistent dimensions, and revolvers that did not have to be filed, stoned and finessed with a lead babbitt to be made to work.
Third, as you pointed out, the PERCEPTION of durability - or lack thereof - and the unfortunate influence of gun writers changed the gunsumers taste in what they thought they wanted in a revolver: larger frame and full under-lugged barrels. That the heavy barrel had no effect on durability was lost on the relatively uninformed gunsumer. Also, the very vocal niche of PPC target shooters wanted a heavy barrel gun they could compete with in service matches right out of the box, and gain a perceived edge shooting cream-puff .38 Special loads. Hence, the S&W 686. Ruger also capitalized on these perceptions with the GP-100 (although they never really broke into the PPC market, which interestingly lasted another 10-15 years until it became like Conventional Pistol: shot only by old men, of all ages).
As for the question posed by the OP.... as much as I like the Security-Six, it wouldn't be my one and only .357. It's out of production many years and NEW parts are pretty well dried up. Repairing a gun with used parts often doesn't work out well with any DA revolver, especially the Security-Six. The old Colts are great, but suffer from the same problem in spades. I don't have enough experience with the newly redesigned Colts, and I also don't see ANY parts available. The GP-100 - hard pass. It's durable enough, but from my point of view the action is clickety-clackety, accuracy is indifferent, it's too heavy/bulky to be all-around gun, and it's grossly overpriced for what it is. The older S&Ws are machines of beauty and function, but having worked on scores of them, I would be paying for a lot of spare parts.
Right now I think the best choice is the currently produced S&W Model 19 Classic, PROVIDED I examined the specimen and it was properly assembled (questionable these days at S&W). Compared to the old-school S&Ws, the new gun as designed is far more durable. Lock neither offends nor bothers me (the guy that bought S&W designed it, so it's not going away). Nothing wrong with the new Model 66, but I don't care for the polishing job on the stainless, and I like blued guns. Nothing wrong with the new 686 guns either, but the full under-lug leaves me cold and it's a big gun for all-around use, which includes CCW.
Great country America, so many choices!