Early 2009 or late 2008 the NPD said that 70% of Wii owners previously owned a PS2.

Doubtful much of that 70% were the core that bought these games on PS2, that or their game tastes drastically changed.

Well in order to be not comparable, the sales would have to be pretty high, something like 500K or higher, which would have been a modest hit (as only the most expensive games would lose money with those sales).

Most people have a PS2 to play PS2 games. I agree with Seece, HD collections seem to do well on the HD consoles, so it's more financially viable to port HD PS2 games to the 360 and PS3. I don't see why any effort should be made to support the Wii, it's obviously not a Third Party selling platform and neither Nintendo or the large publishers feel that it's worth bothering with. 

"seem to do well" isn't proof, especially when about there is only HD collection released so far, and that was of two hit games. That still just proves that his games make hit ports, which I was not denying would happen on the other systems. All you have is the same third party lie about the Wii that they just use BS support to try to prove.

I pretty much asked myself the same question ever since I got the Wii. I wanted many games that were on PS2 (I owned a GC before) that I wanted to play and saw Nintendo's console as a good opportunity 

However, while in theory it would have been a good idea. Sometimes is not as simple as we think.

A port has to justify it's purchase, specially if it was a PS2 game released years back. Just by making it work on Wii and add the Wii Remote Nunchuk controls does not guarantee a hit, there needs to be more content in the game. This requires extra work from the developers and the publisher. The majority chose to move to HD completely.

The second issue is the question: "will the audience like the game if we port it?". Some games, even if they were good on PS2, won't be well received on Wii for many reasons: the fans went to PS3 and Xbox360, the new audience might find the game disturbing, or other reasons. 

I say some developers were dumb to not port to the Wii because their games could have benefit from that, while others did the right thing to not port their games because they won't sell.

I don't think GTA games would sell on Wii as many expect.

That assumes that the audience only supports the HD consoles, which has not been proven. It's only been proven that developers only really support them, and make sure most of the hit games are not on the Wii.

The games have to actually be on a system to not sell. You can't just assume it won't, as that's not evidence.

Well we know that Okami PS2 did at least 368k.  That is assuming it never sold a copy in Europe, and didn't sell any after the first two weeks in the US.  Beyond that it is just speculation.  There are some murky numbers such as Edge claiming 200k sales in NA in 2006.  Also a comment by a US capcom rep claiming 270k (actually that quote is the reason I've wasted so much time looking up sales for Okami PS2).

On the other end there is that less than 600k figure from Guinness, but it wouldn't surprise me if they just combined that 270k ps2 number and the 280k wii number.  I've only actually seen one of the older editions, but I remember it being full of incorrect information or correct but incomplete information.  Similar to wikipedia where the sales information tends to be Japan, US, UK, some combination of the three, or shipment information.  It is all technically correct, but can be misleading.

It's not a lie when Third Party Wii games don't meet expectations. When games like Red Steel 2, NMH2, Fragile Dreams, Batman: The Brave and the Bold and even Nintendo's own titles (Metroid: Other M, Sin & Punishment 2, Kirby's Epic Yarn and Wii Party) don't meet expectations on the largest user base on the market, it's gotta be kinda disappointing. When games bomb on the HD consoles, it's usually because most games are faced with a ridiculous amount of other titles or they are bad games, it's not easy to sell games when you have 3 AAA titles releasing in the same week.

I don't think it's worth trying at this point in time, maybe it could have worked 2 or 3 years ago, but Nintendo and the large publishers put themselves into a tricky position and no matter how many games are released at this point, it's to late. That's my opinion, you can disagree if you want, but I've heard it all before and I doubt my mind would be changed.

I will explain myself a little better about the audience point I made.

Remember Manhunt2? how it was considered a killer simulator? While gamers like us know that those claims are BS, the backfire affected the game's development and it performed really bad in sales because of that image. Just imagine the reaction of GTA with Wii Controls? you and I might think of it as awesome, many that bought a Wii to enjoy with the family will not, and some will backfire. 

Other games just use all the buttons of the PS2 controller and in a weird way that you need a College degree to understand. Transition this to the Wii Controls (the default controller) might hurt the game's original design and the end result might not be a good game

I made a mistake, I should have said that many moved to HD for reasons we already know. As you said, the sales would determine if a port was a good idea or not.

I say we should make a list of PS2 games really are a missed opportunity for not being ported to Wii