"Vaquero and Bisley Vaqueros, Birdsheads and 3.75" single actions sold very well for Ruger"
"And what can they do that a Colt wasn't doing 150 years ago?"
A Ruger SA handgun can handle heavier loads than the Colts of 150 years ago. So, they can do more, at longer ranges.
That comment aside,, I see your thought process. The DW concept was a top idea, in a way, ahead of it's time. Ruger has had a few ideas that were ahead of their time as well. (Example; The 50's era Lightweight .22's,, and now,, the Wrangler!)
Different era, and different feelings by the market & BUYERS!!!!!!
The idea of an interchangeable barrel system,, such as the DW is very valid in terms of performance & consumer expense. Throwing in a potential cylinder interchangeability would probably not happen unless there was a way to prevent IDIOTS from doing as mentioned above, Putting the wrong cylinder not mated to the proper barrel.
But DW handguns proved their performance among REAL shooters,, who understood how to make them work as intended. But the average Joe just looked at the system as a novelty. Often, just one barrel was selected,, and installed, and left that way by the average Joe.
But you have to understand the business concept. A company like Ruger is in the business to make money. And they have bean counters who look at all sorts of stuff to determine if any of the products would be VERY profitable.
So, the criteria is sorts like;
Can we make them with a low enough price point to allow sales to give a good return?
Can we make them in a fashion to where we sell 30,000 a year? (And yes,, 30,000 a year is a figure given to me by a senior Ruger executive long ago concerning annual sales of ONE model. Now,, they may look for a higher number of annual sales,, such as 40,000-50,000.)
Can we build it without spending a lot of time, & money in development for a quicker return on that investment?
Can we build them fast enough to give us a fast turnaround?
What is the current MARKET asking for?
These are but a few things any successful company looks at when it comes to staying successful.
When Bill Ruger was alive & running things,, it was different. it was HIS company. Yes,, he had stockholders, but he was THE boss. There were a lot of projects that were started, that either failed, or were stopped, or whatever. The Hawkeye handgun, the .357 Maximum, (Bill got pissed & scrapped 5000 Maxi's,) are but a few examples. He could get away with it,, because HE was THE major stockholder, and HE made the rules.
No so anymore.
Now,, we have a company, without a founding figurehead like Bill to be in charge, and who could make a decision, right or wrong, and not be over-ridden by others.
It may seem like I'm bashing the current leadership at Ruger. I AM NOT!!!!!!! There was a period of time, after Bill passed away, that the Sturm, Ruger & Company stock was very, very cheap. Lots of things caused the company to flounder trying to fill the void & leadership. No one single person or whatever was to blame. I can remember buying stock for around $5 a share during that timeframe. It took some serious study, some serious reflections on how the company was doing business, and it also took some serious changes in the business model approach to turn it around. The BOD had to make a lot of changes & redirection to make it a strong & very successful company again. They have been very successful in this. It took a lot of work, sacrifice, and changes to make it all happen. I applaud ALL the management folks who did this. But it didn't happen overnight, and yet,, they have succeeded.
But we all have to remember,, they are in business to make MONEY!!! The product is the route to that end. A product has to be profitable,, or it will not be put forth, or if produced,, and doesn't perform,, will be removed.
I for one have been very happy that they did survive & return to the top of the firearm manufacturing heap. Remember,, they COULD have died like other companies,, (Dan Wesson, High Standard, etc.) Or they could have been broken up & sold to other companies,, (Thompson Center, Remington etc.) Or they could have suffered financial struggles like Colt, & others, only to have been bought out by a FOREIGN company.
Nope,, I'm happy Ruger has succeeded as they have. They may not make everything everybody wants,, or they may not do all we wish they'd do,, but remember,, they COULD have gone away,, and we'd not have ANY new Rugers or such.