It has been a very slow start for the PS3, but this is solely down to cost. Sony will put pressure on PS3 developers and will push to get BluRay players produced for rock bottom prices.
They will hope that the forthcoming PS3 games and potential BluRay popularity will push for more PS3 sales over the remainder of the year. The big period is Xmas and they will hopefully see:
a) a decent increase in sales
b) a large selection of quality titles
c) vastly reduced costs for PS3 components (inc. BluRay player)
So that they can make the huge decision at Xmas to reduce the cost to bring in the huge customer base.
The Wii will have a pretty big customer base over the next few years, but the longevity of the system is in question. The PS3 can have a huge lifespan and may take another 2 years to start building up the customer base, but this won't be a problem seeing as the hardware will easily last for a long, long time.
One problem is the PS3 is much more expensive than the 360 and Wii at the moment...it's double the price of the basic 360 and IMHO needs to drop $100 or thereabouts at least in the next 12 months with a further $100+ drop to happen within the following 12 months from that.
Prediction (June 12th 2017)
Permanent pricedrop for both PS4 Slim and PS4 Pro in October.
PS4 Slim $249 (October 2017)
PS4 Pro $349 (October 2017)