@KPCT , the most important thing you said is "One should calculate ROI on total investment amount and not only on alloted IPO amount".
I too believe that the ROI may come down with more and more new entrants.
Take example of Tata Tech, usually 50k+ bHNI applications was a big deal while TATA Tech managed to get close 120k bHNI applications.
Till now my ROI in IPO's has been decent but I'm afraid going forward it may come down.
I actively moved into the primary markets from being a decently profitable options trader (as the expiry movements were getting wild with new entrants in option selling).
So, there may come a time when I have to leave the primary markets too for something else as I don't want to play the game where my probability of winning is less.