The loss that needn't be

Nowadays I come across a lot of people (not physically, of course) who are saying that the losses that their equity fund investments have suffered means that the idea of equity investments for the long term stands invalidated. Here's a typical such view, from an email I received: "Even long-term disciplined investors (investing for the last 5 years or so) have lost their money. What is long term now, is it seven to 10 years? What should such investors do now?" The writer then gives an example to illustrate his point of view, which consists of the five-year change in the Nifty from 23rd March 2015 to 23rd March 2020, the latter being the date on which that index made a low of 7610 points. On 23rd March this year, the Nifty was 11 per cent lower th