But The Shield have been booked very strong since their debut. Mostly every time there's a brawl their always toe-to-toe with their opponents. Hell, they WON at EC. Over the top face of the company. Seriously, they have to lose eventually. The Shield have had only 5 matches, and they won them all. But you can't booked the dominate forever, eventually they will have to lose. And it makes all the sense in the world for their first loss to be at the hands of the guy they've screwed over time and time again, Ryback.
And you mention how, "if you book a team in a week manner, people won't buy into the team." But, what about Ryback, if these guy's keep beating him, and causing him hell, than Ryback's not going to look strong enough anymore. Trust me, they've booked The Shield strong for awhile, but it's time for Ryback to put an end to his feud with them. Just because they have one lose under their name doesn't mean their careers are over. They've just debuted what, 5 months ago? All three of them have a long career ahead of them. It'll be their first loss, their FIRST loss. It's not like they've lost every PPV match they've been in for the last few months like Ryback.
The thing is though, yes, the Shield has been existent for around 5 months, however, it is still too soon for them to break up: none of the wrestlers have been given much personality yet by creative, and it is dangerous to break them up now, as they might damage them. So, if the Shield is to stay together, they need to continue to be booked strong to retain the position they currently hold. Ryback was booked as unbeatable before getting a mega push from weakly jobber killer to WWE championship number one contender, and it didn't go over too well. At PPV's you could literally hear how indifferent crowd were compared to him in comparison to other wrestlers. The Shield, however, is currently popular, they have been a success. Now yes, it is OK for Ryback to get a win, but it should be in a lower card match, or at least not against top young incoming superstars like Ambrose, Rollins, and Reigns. And yes, the Shield members' careers wouldn't be over in the case of a single loss at WM, but what good would that do? It would be a boring, pointless, usual team of faces VS heel stable booking, just as in Team WWE VS Team Nexus and in Team WWE VS The Alliance, and so forth. And yes, the Shield will have to lose sometime, but not yet.