Well, IMO One of the Boys was a better album quality-wise, so I think she can definitely top Teenage Dream in terms of quality. But Teenage Dream will be her peak with success most likely.
I doubt it, the TD era has been so amazingly successful singles-wise, I'm still in awe of it. 4 number one hits in a row followed by a rising near the top 5 single.
Quality wise, yes. I think she's going to have an era filled with good songs, but not a lot of hits on the charts.
Again, she (and her producers) found this magic "pop formula" that just oozes number ones and hits. If they want to make more money, just continue doing the same and change only a little bit. But again, it depends on which road Katy wants to going to her future albums. She's still young and popular enough to continually strike out singles. I think that if she copies what she did in TD and tweak it a little so it's not the same thing, then she will come close to TD. But I highly doubt ANY album would have success that TD had on the charts.
Success wise, I don't think so, I mean realistically speaking how many times can you pull 5 #1s off one album, so NO.
Musically speaking, she may top it because TD wasn't as great as it could've been altogether as an album, so her next album might be put together more.
Single wise - NO
Sales wise - Hopefully... TD should have boosted her profile, thus giving her chances to sell more albums
Quality wise - Hopefully, she has more to offer than fun, catchy, disposable pop music. I would like to see her artistry more.
I think it's possible. Rihanna went on after GGGB with success and people gained even more respect for her. I think the same will happen with Katy. If the public keeps eating up her music the way they are now, who's to stop her from getting those #1s?