The OP can't lay all this on S&W, and S&W quality assurance has not changed as much as you'd think, and it's changed for reasons the OP may not have considered. The bottom line is that S&W is running a business and the level of QA is determined by costs versus benefits.

In the 1980s it was the norm for good local gun shops to carefully inspect each new firearm that arrived in the shop - and to reject those firearms that had flaws. When a defect was found the wholesaler or the factory would be called to arrange for a return and replacement. However, most of the time the initial response would be an offer to reduce the price on the gun to very low levels,with a credit going to the shop, who then kept the firearm and sold it. Credible shops would say "no thanks" and return the firearm.

Once the wholesaler or factory got it back their response when the defect was cosmetic or non safety related often wasn't to fix it, but rather to offer it up as a factory second to a department store or other big box type retailer, where they'd use the discounted cost to sell it at a steeply discounted price. Remember, you get what you pay for...

Under that business model, local gun shops charged more for the same model firearm, but you were getting not just the firearm, but also the QA and warranty services from the local gun shop. You could buy with a high degree of confidence that it would be perfect, and if a defect surfaced after the purchase, the LGS's response would be to replace it out of existing stock, and deal with the factory on the return and repair issues, rather than stick the customer with that. If the arm was replaced it was sold as new, if it was factory repaired - and met the shop's inspection criteria, it was then sold as used, offering someone with a really good deal. If it did not meet the shop's inspection criteria it was again rejected and sent back.

Today however, local gun shops have greatly reduced the services they offer with the sale of a new weapon. I've bought firearms in some shops where I'll look at the one on the counter very carefully (since the LGS can no longer be relied on to do a thorough inspection) only to have them bring another one out that is still in the unopened box that they actually plan to sell. Their point is the one on the counter is a display model that has been handled. My point is that's just fine, I'll take the one in the box - but only after I do the same thorough inspection, and if I don't like it you'll go get me another one to inspect.

Also, if I discover a problem, such as severe leading from an improperly cut forcing cone, I'm now the person who has to deal with the return and repair issues, as the LGS is probably going to limit its involvement to giving me the customer service phone number.

In summary, S&W's QA isn't all that much worse than it was in the past. In the past, less than perfect QA was back stopped by an inspection by the LGS. The LGS was aware of QA failures, but those firearms never found their way into customers hands - unless they went via the department store route, and those customers tended to be less discerning and never noticed.

If a customer did notice a defect, he'd bitch to his friends, but it quickly diluted to hearsay and never got much distribution as a credible complaint - and he probably already had a replacement in hand from the LGS, so it wasn't a big deal.

Now, there is no LGS QA backstopping the factory, and the customer is the one stuck dealing with return and repair issues. And that customer can reach hundreds or thousands of people with their complaint of poor quality.

Which of course means that more defects are reported to a wider number of people, which creates the impression that quality is worse than it used to be. It isn't. It's just a case of each defective firearm being more noticeable. And that won't bother S&W enough to improve quality, unless it actually starts resulting in losses of sales that are sufficient to offset the costs of a higher level of QA, and rejection of more firearms before they are shipped.

Finally, in my experience S&W is much better at QA than Ruger, and they have better customer service. And Ruger is lighters ahead of Taurus, where I have doubts that any meaningful level of QA even exists.