I think this is the discount? It looks like it was from 2012.
http://www.playonline.com/ff11us/topics/ffxiv/
(Edit: Someone beat me with the link...)
Personally, as someone who doesn't have tons of free time for mmo, I don't play 2 mmo with sub at once. It is a waste of money to pay monthly fee for 2 games if I only have 1hr of free time for games per day.
Therefore if I want to play ff14, I would cancel ff11 sub and vice versa.
Discount doesn't change my decision. Even if ff11 sub price drop to $1 it is still $1 wasted if I don't have time for it.
The kind of consumer that SE can get with bundled discount isn't someone like me, who will never play 2 mmo at once, nor someone like Proth, who pays for 2 subs regardless the price.
I believe ff14 player who wants to play ffxi bad enough will pay without discount anyways, there are many ffxiv players new to ff11 without discount on Reddit.
(Edit2: as for people who know nothing about ff11 and need a bit of push, ff11 has free trial for them too. Even better than $7 monthly fee.)
So this bundle discount strategy
probably only works on "uhmmmm I
kinda want to go back and *** around in ffxi if the price drop, but not really....." people.
The real question is, how many people are like that. And more importantly,
how long will these not-so-serious player stay? If they stay do they stay for long enough to outweigh the money loss from die hard fans that keep 2 subs active forever?
I am more inclined to believe that if this discount was offered in the past but not anymore, then they probably have at least some data to support the current pricing decision.