So we've spent a little over 10 years to get nowhere in nominal terms, and meanwhile the value of money has dropped by approximately 25%.
Yes, shares pay dividends, but most people buy them as part of some collective arrangement that involves initial and recurring charges and/or fees. After charges (and taxes, remember), it would have taken a net dividend yield of about 3% per year simple, or 2.65% compound, merely to replace the value lost to inflation.
So quite possibly the putative investor in the FTSE has actually fallen behind where he was in 1998.
Are the pessimists lagging behind the news? Has the worst happened already?