If they both launch at the same exact time, it will boil down to this: Supply.

Which company has the resources to break the trend and manufacture a few million consoles for launch? Seriously, a great initial supply with killer marketing at launch could make some serious damage. I can see Microsoft prevailing in this scenario but I guess we'll just have to wait and see.

For Sony the damage is done. MS swayed a ton of people to switch brands and then shackled them with a Gamer Tag and a Gamer Score. All those people that keep track of their chievos will not leave them behind. MS knows this and will make sure their complete Gamer Score will be waiting for them on the Next Box.

Next gen is going to look a lot like this gen. The only difference I see will be that Nintendo won't sell record numbers to soccer moms and grandparents. I think it is far more likely we will see a fairly even three way split than see Sony take back their lost customers.

So you don't expect Microsoft to publish any 1st/2nd party games next generation?

The possibility of migrating profiles to  the newer system will surely have impact on sales for Sony and MS.

But I doubt it will stop anyone from buying a console of another company.  Whoever makes the better console will steal market share from the other.

Except last year when MS sold 800k more.

I don't know if Sony wants to push up the launch of the PS4 in order to match the 360. We're seeing a pretty dramatic shift in strategy from Sony this gen. Last gen they were extremely aggressive price wise and were ok with making less money selling hardware in order to eat up a lot of market share. Due to their financial troubles, this generation seems different. They should have dropped the PS3 and Vita prices already but have not because they make money (or lose very little in the Vita's case, idk what the total cost per unit is there, I read $160 but that was before R&D, marketing, etc). So it makes more financial sense for Sony to just ride out the PS3 as long as they can and continue profiting off of it,

A year head start is nowhere near as important this gen for MS as it was last generation. MS has improved their brand name immensely and now basically have the biggest market (US) in the bag.

Xbox360 out 1 year before PS3 so it had more game then PS3 and had supeior version of multiplatforme and was a way less expensives then PS3 and yet Xbox360 is only 1.9 millions ahead.
If Sony wont do the same error with the PS4 then what they done with PS3 the xbox3 won't beat it.

Lol!

I'm pretty sure except for the hardcore gamers, no one cares about gamertags or gamerscore, myself included

If i switched over to microsoft next gen i couldn't give a stuff about my psn profile, the whole achievement/trophy hunting thing is a niche

Why lol?