2 Things - Timing of the launch and Price
I doubt they will get out of the gate before the next Ninty and Microsoft system, however I think them lagging behind MS this gen really hurt them, they are slowly starting to catch up on software sales now though.
I have a lot of friends who will buy multiplayer games for 360 because everyone has one, and not everyone has a PS3. I was one of those people as well, as I was frustrated with not being able to find a PS3 anywhere I looked so I bought a 360 to "tide" me over.
Regarding price, I could be wrong on this, and I am sure if I am then I will get 20 replies telling me so, but I think the biggest reason for the cost of the PS3 was probably due to the BD player, I bought a launch PS3 and paid the $599 or $699 (?) price at the time, however, BD players that weren't even upgradeable at the time were selling for $100-$200 more than that.
If PS4 goes with a different storage media for it's system and that jacks the price up again, I will be disappointed in Sony (but will still buy the Ps4 - might have to get a second job)
However, I think they should/will stick with BD for the storage media and by the time the PS4 launches I think the cost for them to manufacture the drives will be minimal, and depending on the other specs - I think the price will be a more reasonable price (maybe not $299 - even PS2 Launch price was higher than that)
Unicorns ARE real - They are just fat, grey and called Rhinos
