On the issue of Eternal Champions, I haven't any idea how many it sold total, or whether these are accurate, but here are some old charts from NeoGaf.
Bare in mind, EC came out in August of 93, when Sega was at its height (ever).
Jan 1994: Etetnal Champions was the No2 game of the month, selling about 65k.
Feb 1994: EC at no4, with 40
March: EC at no11 with 30k
April: EC at no18 with about 14k
May: EC at no24 w/ 9k
June: EC at 19 w/ 12.5k
July: EC at 28 w/ 10k
http://m.neogaf.com/showthread.php?t=116454
What people need to remember is that EC was a game from Sega. Most people who brought the MD were more likely to try out or buy Sega games first before any other game from a third party. Sega at that time had a great reputation. Fighting games was the big thing. So when Sega released EC and with all the hype...people lapped it up. Just like Nintendo fans lapping up Killer Instinct. No difference to Sega fans lapping up a title from Sega in a genre everyone was going gaga for. Depending on who was making it.
Also as i said EC sales are down to various factors.
Initial sales (title sold at full price)
Rebate sales (title sold at special rebate price via promotional deal)
Activator pack in sales(sales for systems or preperials count towards game sales depending on the game included with system)
Genesis pack in sales(special exclusive shop deal pack in)
That's effectivly how the game managed to get the 2 million i spoke of.Like i said anyone who knows about these type of things would know that or know how the industy and specifically Sega count sales.
On top of that when SOA licensed Tiger Electronics Sega IP for their LCD Sega Arcade...with VIRTUA FIGHTER, BUG ETERNAL CHAMPIONS and a few others...EC SEGA POCKET ARCADE sold 18 million units.
So you can see why SOA wanted to go full steam ahead with this property. And why SOJ didn't since the VF version of the title didn't sell as much. That is why SOJ feared something similar may happen with EC 3 for Saturn and made sure it and other genesis titles didn't happen.