I'm in California where we have been restricted by the handgun roster to only having the Shield 1.0 because no new guns have been added to the roster for more than a decade. I've daily carried the Shield 1.0 for 8 years. I practice with it. It goes bang, every time, it's reasonably accurate, it has never broken, malfunctioned FTE or FTF. Not once in about 6,000 rounds. I thought that it might be getting a little tired after EDC for 8 years so I upgraded to a Shield Plus Performance Center. Trigger, grip texture, sights, magazine capacity, it has a ported barrel and slide, everything about it is better. I also have a Glock G17 Gen 3 that I sometimes carry, although it gouges me in the side when I sit down or drive because it's big. As far as quality and reliability between Shield and Glock, there is zero difference in my experience. I like Rugers too so I added a Max 9 to my CCW because I wanted to try out a green dot CCW pistol. Jury is still out on carrying a green dot but the pistol itself is decent. Trigger isn't as good as the Shield Plus PC.
The Shield is popular because it's a good gun. Whether or not you like it is your choice but millions of Americans disagree with you. Not saying it's the "best" CCW gun on the market but it's well built, reliable, easy to shoot, thin so easy to carry, etc. The SIG P365 outsells everything else on the market because it's tiny and holds a lot of rounds but I find SIG reliability to be questionable, at best, I've owned three SIG handguns, they have all had defects, had to go back to SIG for repairs under warranty and still had more problems so I will never buy another SIG.
I judge guns by how they work for me, because that's all that matters to me. The Shield 1.0 and the Plus for the past year have both been rock solid, no FTEs/FTFs, nothing has broken on them so they're both fine by me. I think Springfield/HS Produkt make good guns too. I would consider the Hellcat if I could by one without off roster extortion prices, but eventually, we will lose the roster here and we'll be able to buy any gun like people in America can.