No it did NOT have to happen, that's just retarded, not every Ford has to be the same car built off the same platform, there's comes a point where cost cutting cuts into your profits because people aren't willing to buy what you're selling.
And yes the Taurus is better than a Camry, but certainly not even close to a Falcon, it's a completely different car.
What Ford needs is a global RWD platform that can underpin the Mustang/Falcon/Territory/several Lincoln's/Explorer etc.
If Ford is attempting build the best, trying to build everything off of inferior 80's minded FWD only platforms isn't the way to do so, like I've always said, if I wanted to buy a Toyota I'd buy one. RWD isn't a "niche", and it doesn't equal poor economy, the 30mpg 305 horse 2011 Mustang V6 proves that.
Holden will be the biggest beneficiary of this error, as long as they don't surrender to the bean counters as well.