Disgaea sold better on PS2 in Japan undoubtedly, but I can't find any evidence for the overall or NA sales of the last two games so I don't know what you're basing that off of.  Since we've already seen that the Tales audience in Japan is strongest on PS3/PSP I assumed your argument was about the fanbase in the West and therefore you disagree because Disgaea 3 sold less in the West than 2 and 1.

according to famitsu,Kinect sold 40000 in Japan

http://kamome.2ch.net/test/read.cgi/ghard/1291711161/327

first week:16911,2nd week:10882,3rd week:12683

Last year it had a similar FW but ended up at 400k . I expect at least 300k again which is decent really

Tales of the Abyss and Legendia unlike the Wii en Xbox 360 entries didn't even get a PAL release, and there hasn't been single Tales that has been markteted as much as Symphonia, which in Europe got bundles and was translated to all the important languages.

I think that Abyss could have performed well on the PS2 in the US if hadn't been released so close to FFXII and a little more marketing could have helped. Legendia had awesome music, but it is a pretty forgatable JRPG.

The old NPD spreadsheet I have puts the first game over 150k after just over a year on market.  The game got several reprints after that (due to high demand) and even a GH release still, so upwards of 200k is probably a good minimum bet (and reality is probably more 250k-plus territory).  You can actually piece together a lot of this info if you google "bunkum" and "Disgaea" to bring up the old NeoGAF NPD leaks.

Symphonia only got the royal treatment in Europe because Nintendo published and promoted it themselves.  And it paid off iirc (over 200k sold).  If Namco (or their various distro partners like EA, Ubisoft, Atari, etc) had handled it, then it'd have gotten the same terrible treatment the rest of the series did.  I kind of wonder if NOE wouldn't have been more receptive to doing Graces if Namco wasn't planning a significantly enhanced PS3 release within 2 months of it's release?

In the US, Symphonia had basically the same level of promotion as Legendia/Abyss (just some internet and print ads), yet it dramatically outsold both combined.  Symphonia actually even outsold Abyss just just counting sales starting from the release of the latter game, Namco made a GIGANTIC mistake not having a GC version for the west (same deal goes for Soulcalibur 3 actually).

I think Graces Wii could've done better in Japan if it hadn't released alongside FFXIII, and wasn't a bug-ridden mess. The negative word of mouth spread pretty fast, which is also why it's legs bottomed out completely (even compared to other Tales games).  Would've probably sold 250-300k then.

But what about Disgaea 2?  Your statement is supposed to be talking about the series as a whole.  So here's the best I can figure for Disgaea 2 sales.

According to a statement from NIS they have sold 1.6m Disgaea titles total.  Taking out all the sales we have from Disgaeas other than 1 and 2 that leaves us with 770,000.  Taking out the Japanese sold for Disgaea 2 and if we're nice and give you 250k for Disgaea NA sales that leaves us with 370,000 to be split between Disgaea 2's NA release and Disgaea 1's Japan release.  Once we're there we can either assume Disgaea 1 sold the same in Japan as Disgaea 2's 150,000 leaving Disgaea 2 with 220,000 NA sales but in my mind the more reasonable conclusion would be that the original Disgaea sold more in Japan and it only takes 200,000 sales of Disgaea 1 in Japan before Disgaea 2 is dipping below Disgaea 3's NA sales. 

This was all done also assuming that the first two games sold absolutely nothing in EU, which may or may not be reasonable and not taking into account that NIS probably means shipped, but with a tiny game like Disgaea I doubt there are a ton of them sitting on store shelves.

Doesn't seem to have bottomed out any sooner than other Tales games.  ToS2 on Wii had a ratio between FW and LTD of .655 while ToG has a ratio of .636 and ToV PS3 had a ratio of .642.  The only recent console Tales I see that doesn't follow that pattern is ToV for 360 which has a ratio of .57 which I would be inclined to chalk up to the smaller user base of the 360.

Disgaea 1-2 did sell basically nothing in Europe (where Koei handled them). Disgaea 1's impressive US sales are actually what led N1 to establish NISA iirc (Atlus USA handled the first game here).

I wouldn't be surprised if D2 and D3 sold within the same ballpark though, but mixing trackers and then doing some fuzzy math with shipment data to try and arrive at a comparison is a slippery slope at best.  But D1 was the real breakout... this is all pretty tangental though, as it really has little bearing on how a PS3 Tales might do, except arguably to draw a negative conclusion based on past performance (Disgaea sold great on PS2, Tales really didn't).

I'm talking purely original mothership releases, like Graces.  And this is the data set I'm looking at, which directly covers 70% of the JP market (and estimates the rest)...

• Tales of Innocence (DS) 106,733 (246,240) 43% fw
• Tales of Vesperia (360) 101,272 (204,305) 50% fw
• Tales of Hearts (DS) 141,610 (261,751) 54% fw
• Tales of Graces (Wii) 143,309 (197,509) 73% fw