laterifer7,, NO problem offering thoughts to your questions. That's why we are here & many of us try to help.
It's often lamented that a maker of stuff "should make XYZ" to satisfy the desires of some customers. Ruger included. But,, you have to accept the fact that they are in business to make money. The guns are the route to money. Demands must be strong enough to where a profit is projected to be good enough to allow for a return on the product.
A good example.
Decades ago, Bill Ruger wanted to build a gun to compete with S&W in the DA revolver line. He developed the Security-Six line of handguns. BUT,,, it was not a big profit maker. Bill was the man in charge & what he wanted was done. In fact the story is, that the Security-Six line lost money,, but became a thorn in the side of S&W. Later,, they developed the GP line,, and it makes money. And while they lost money in the Security-Six line,, overall the company made good profits elsewhere to accept that loss.
Bill is gone, and there isn't any Ruger family involved in the company. The company is run by a Board, and the goal is profit.
I was speaking with a (now retired) senior executive several years ago. We were discussing a specific model. It had been out for a year, and he commented how they had sold 30,000 of that model in a year. He said that was a very good sales record.
But to try & fulfill all the desires of customers just won't happen if the demands do not meet specific sales numbers.
That's why many custom gunsmiths are in business. They take a base gun, and transform it into what a customer desires. A recent example was a person here wished for a Single-Six sized, 5 shot,, .38 spl. That's a very low demand item. BUT,,, a few customs have been built for people wanting that type of gun. On the other hand, for many years,, people were taking the OM .357 Blackhawks & having custom .44 Spls built. Enough so, that Lipsey's distributors ordered a special run of a few thousand of them. They were popular enough that Ruger put that gun into regular production. AND,, here;s the key point. It was an EASY conversion when it came to Ruger engineers & designers. A low cost change & a good profit return.
So, while the SP-101 line is strong, and certain models were available, many are not kept in current production due to slow sales/demands.
In simple terms, "It's just business."