From the outside, Alphabet seems to do a very good job when it comes to engineering. They have very little downtime, fewer embarrassing security moments than most, youtube is far better technically than the competition, etc.
It's just that they aren't building things that people want to use, but that's a failure of management and incentives.
Thing is, they actually are building things people might want to use, they just don't focus enough on it. Stadia for example, was way ahead of Microsoft in image quality, fluidity, etc. After a year or two of trying to push it to customers they killed it for no reason whatsoever.
I even recall watching some comments of sad people who would need another gaming streaming service because they used Stadia for their gaming needs. It was a ridiculous decision that nobody understood why. They also screwed up game devs who were porting their games to Stadia, which will for sure have repercusions in future services.
It's just that they aren't building things that people want to use, but that's a failure of management and incentives.