What are you talking about, I don't like DDLJ one bit but it finds audience, it finds audience in MM, and as Jatinder said, DDLJ is sometimes showcased on valentines day and few other special occasions, it's there because it finds audience.
Shouting PR, PR, doesn't makes you sound smart, it makes you sound like a fool, no amount of PR can work unless you can show results.
Besides is is really your concern or is it your jealousy that no one gives a shit about so called iconic record breaking marriage video of Salman?? Does it pains you to realise that despite being smaller ATBB than HAHK, DDLJ has been more relevant throughout the years, that after all these years, DDLJ is still relevant among different generations whereas HAHK is being treated like an outdated movie which it is??