Oh I'm so tagging this one. On duty right now but when I get off I will share my opinions and those of my father. We're both cops, shooters, GLOCK fans and also S&W fans.
My father was one of the first police officers in the United States to carry and qualify other officers on GLOCK. Before that he was a S&W Wheelgun guy.
When GLOCK came onto the scene S&W was having troubles with their guns. Yeah, we have good S&W guns but S&W as a customer service related company and quality control company it was not. Their quality was slipping and the same was happening with Colt, Ruger, Remington, Winchester, and others on the American market. GLOCK provided a product that was revolutionary, dead nuts reliable, and they had a great customer service.
They jumped into the market at an amazing lucky moment. The FBI Shootout, Rising crime rates, Cops feeling under gunned, etc... Their marketing was great and they basically gave their guns away to LE Agencies for free. A one to one swap or very little cost per pistol. They would then sell the used on. They took a hit in sales to LEOs not in numbers but in profit. They did so for free marketing. When the civilian populace sees cops everywhere carrying GLOCK they will buy them.
The customer service they provided was amazing and still is to the LE market.
Smith & Wesson on the other hand was floundering. They were producing a different gun a week and had to many models and variations. GLOCK had one and then released a couple of others. They stole the thunder from S&W with releasing the Model 22 in .40 S&W faster then S&W did. It also was lighter, had a higher capacity then the S&W models, and had a single trigger pull from start to finish.
The majority of cops are idiots... they are not gun people. The fact that the GLOCK was and is a safe pistol to carry and has no external safeties made it easier to train officers to carry it. Much like the S&W revolver except it was lighter in weight, had less parts, and carried three times the amount of ammunition then the revolver it replaced.
S&W was later sold to the British holders and that further shot S&W in the foot. Officers would not want to carry pistols that were made because of a political deal with the Clinton/S&W HUD agreement. They want to carry what they think is the best gun. Even HUD's IG Agents carried GLOCK.
The copy and horrid release of the Sigma is further proof that S&W was hurting and hurting bad. They couldn't come up with a design of their own to the point that they did a horrid copy of the GLOCK. They were later sued for it.
The SW99 while a great gun once again showed the market that they couldn't come up with an original design. A Walther pistol in S&W clothing and the further recall issues and failures with the NJ contract (NJ screwed that one up but the general public didn't know the gun was a dud due to NJ requirements and not S&W).
S&W, Colt, Ruger, etc... were all suffering from the mindset of being unbeatable. S&W was dethroned from the top LE market the same way that Toyota dethroned GMC and Ford in the car market.
A dead nuts reliable product at very affordable prices with some revolutionary achievements and great customer service.
S&W is taking back some lost ground but the M&P is also showing issues and S&W is still having customer service issues. While they will bend over backwards they will not admit that their is a problem with the M&P 9mm due to the barrel, chamber size issues and lack of accuracy. Their answer to that is that most shooters can't shoot worth a damn so they won't notice the lack of accuracy. But the problem is bad enough that APEX is going to release a barrel for the gun that solves the problem. S&W is also putting their eggs in the M&P basket... which is smart but stupid at the same time. They are competing against themselves with the Sigma and SD Series on the civilian market.
GLOCK is going to be king for a very long time. The same way that Samuel Colt achieved great success, Gaston Glock did also. GLOCK continues to produce what the customer wants (Government market). S&W keeps trying to have both government contract market and the civilian market at the same time. They need to simply focus on a core group of products for the government market and their pistols will sell will on the civilian market due to the buyers wanting to have what the cops carry.