Are artists not strong enough to release songs by themselves these days?????

I think for some it's a way to boos a profile. Others they are just general collaborative people and it's lucrative to feature as again it boosts their profile.

A good example is Katy Perry in 2010 featuring on two big collabs before releasing Teenage Dream which made her a superstar. It boosted her profile reminded people of her and gave her a great platform to launch the album.

It's been happening for years.....
Sonny ft Cher
Elton John ft Kiki Dee..... Er can't think of any more at the moment

Those were proper duets rather than just tracks featuring someone. Both artists were equally as important to the track

I'm 'old school' but I hate it when the artist is listed as 'X versus Y feat. Z'.

I've noticed that many tracks only 'feature' someone once it becomes a hit and/ or the 'guest' vocalist becomes known in their own right. This especially seems to be the case if the featuring artist is relatively un-known. By way of example, OTTOMH I recall that DJ Fresh's Hot Right Now and David Guetta's Titanium didn't use the 'featuring' tag until Rita Ora and Sia respectively started getting more exposure. They were just tracks by Fresh and Guetta.