Vince Clarke did:
First Depeche album
The Assembly
Two Yazoo albums
Five great Erasure albums

And then...

Suddenly he hit the dumper and hit it hard. Having bought all the aforementioned, I couldn't be bothered with I Say I Say I Say. To this day I can't tell you why not. - although Abba-esque was poor, and not a patch on Erasure-ish.

The only other example? Phil Retired Collins.

...about Elvis?

"He got what he wanted, but lost what he had".

Though, admittedly, Presley's subsequent career was more successful than Erasure's post #1 slide...

There's a new Depeche remix album out soon and he's one of the remixers, and not just of his stuff. Odd.

Any other artists who took a similar career nosedive after hitting the number one spot?

and they were ahead of the game with that considering how big ABBA have been ever since.

After years of graft, you finally made it big. Very big.

You did it first with the Ants, then continued the momentum as a solo performer.

You now have the chance to make the next step - the really big leap forwards.

At your disposal is a slot in front of a massive worldwide audience, a major charity bash in the company of the world's rockular elite. Fifteen minutes to cement your place in history.

Do you...

a) Play a medley of your greatest hits, your strongest songs - pleasing both the fans and the casual listeners;

or do you...

b) play a couple of songs no one has ever heard before from your upcoming new album that, frankly, stink the place out?

Oh dear.

'Dizzy' with Vic Reeves hits number one. Lights up indie disco dancefloors across the land but band's credibility nosedives and career stalls. Split up after next album.

(Pretty sure the reformed Wonder Stuff don't include it in their sets these day!)

The tunes got less interesting as fashions changed. I don't think being ABBA was anything to do with it at all. Unless it scared off the non-gays.

It's the late 80s. You are second only to Morrissey in the arty, sensitive student pin-up stakes. You are very British, despite obvious American influences in the music. You're culty and cool but you've had plenty of hits. Life is good.
So, you split the group, grow your hair, grow some stubble, move to the US and go rock. The album is very good but it doesn't find new fans and alienates the sensitive old ones.
You go even more American, your next album has 'Babe' in the title, mixes more rock with Burt Bacharachy string drenched concoctions. It's very good but alienates even more people. A flop.
You go even more rock, write some terrible songs and dress them up with unfortunate modern production and call the result Bad Vibes. Everyone, including you, hates it. Career more or less over.
Soon afterwards you refind your mojo and spend the next 20 years releasing wonderful solo albums but hardly anyone is still listening. Bugger.

You've been pretty much at the top of your game for two decades.

Hell, you been pretty much at the top of everyone's game for the past 12 years.

You release what will be your biggest selling song ever.

One of the Top 20 selling singles of all time in the UK alone.

And you watch your career and your future reputation go right down the pan.

You are Stevie Wonder.

And I bet you wish you'ld never "called to say I love you".