I have read many posts of people saying they are sorry to have missed Bitcoin. But I wonder if they realise that there have been more than 20 trains out there that could have made them millionaires.

They have managed to miss at least all these, some of them as recent as July last year. It is not that you missed Bitcoin, is that you (and I) just missed many many others



NXT          2013-09-28            +1084215%
IOTA         2015-11-25            +418179%
Neo           2015-10-01           +354482%
Ethereum   2014-07-22           +265772%

And the recent ones...
Populous      2017-06-24          +12181%
QTUM          2017-03-12           +10091%

Be honest to yourself... you did have a chance!