At this point, no one should be surprised. Winning is basically what the Astros do. And even with ups and downs during a long season, it's clear they are as good as the team that won it all last year and have the chance to be better.
What is perhaps most incredible is that this is not an old, veteran team. The roster is about as balanced between veterans, players in their prime and young talent as any team in baseball. Three of the Astros core four (Bregman, Springer, Jose Altuve) were in this All-Star game and there is an argument to be made that Carlos Correa, had he been healthy, might have gotten a nod as a reserve. None of them are 30 years old yet.
Bregman, who is having a breakout season, is 24 and already one of the most reliable big game, clutch hitters in the sport. He is responsible for more of the team's walk offs than anyone. And he is just one of the guys on this team with the ability in the clutch. Both Altuve and first baseman Yuli Gurriel are in the top 10 in batting with runners in scoring position.
The simple fact is the Astros know how to win and most of them have learned it before they turned 30, which puts the bulk of the guys in their prime when the team is absolutely stacked with talent. There is no point in talking about dynasties until they have won more than one title, but this is certainly a team poised to be extremely good for the next few years and part of the reason was on full display in extra innings in the All-Star game.