The plan is to have the F-35A price down to US$80 - 85 million flyaway cost by 2020. The current flyaway cost for a new F-16V is around US$70 million, maybe $75 million. So there is not really that great a difference in cost between the two, but capability wise the gap is huge. If they have a budget of US$x billion for new combat aircraft acquisition then if the F-35 is selected, they will obviously acquire y number less aircraft than if the F-16V was selected. However the number of F-35 aircraft capability wise, will outweigh the number of F-16V aircraft that the equivalent budget could procure.
Fair point on that but that assumes they are looking at the F-16V variant, There are a few options available to them that are cheaper variants.
If the impending UAE order for extra F-16E/F's block 60 is anything to go by with spares and all the other required componants they could get there F-16's for a total price of $70m a unit with all the required spares and support.
Dont get me wrong, the F-35 is a major leap over the F-16 but where they already have experience with the F-16 and personnel and procedures in place to deal with such an aircraft they dont have that with the F-35 and that will play into it because that is exrta expenditure on an already tight budget.
My best guess is that the mig 29's and Su-22's will be replaced with F-16's within next few years while the older C/D model F-16's will be replaced with F-35's mid 2020's. The Polish def min has stated that he thinks now would be the wrong time to purchase them, had they joined the program 5 years ago and Polish companies got a slice of the pie they would have but now he believes that it's best to wait until FRP with higher availability and lower unit costs.