June 15th 2006 to June 15th 2016 returns 38% capital growth with dividends reinvested.
Try and get that in a bank.
And no, it's over 6,200 at present.
The FTSE 100 is also just one index of the 100 leader shares on the Uk index by capitalisation. The S and P 500 has double that return over the same period.
But to be honest, very few investors simply invest in a single index which is scattergun approach rather than trying to buy value.
And as I keep repeating, 100bn hasn't been wiped off the nations wealth, the money has simply been liquidised to cash/bonds. The wealth is still there but pension funds are always cautious and will stock up their lower risk assets ahead of an election.