Another bias I would like to bring to the fore front. It is adviced to invest for ten years. But I simply don’t see the practicalities of that statement.
Assuming that we are talking about only the companies that have it in them to maintain good fundamentals for a stretch of a decade. That brings us to only 5% of all the listed companies.
Even they, in fact especially only they, get exceedingly expensive to the point that there is no sense in staying invested.
For example… Since 2008 Infosys has given very dull returns. Going forward Maruti is likely to be a dud.
A portfolio has to be dynamic, but only as much as is necessary. It cannot be a legacy.
The data you have analysed suggests that one could buy an Index fund and remain invested in it for a longer stretch and it would be fine. Even then, one must react to the PE levels. Because a ten year stretch has two five year periods. If one only reacted to expensive and cheap PE levels good returns would be much better than simply holding.