The F-35 is slower, less maneuverable, more lightly armed and has a shorter range that the F-16. Its only plus is stealth. But stealth is a function of the enemy’s computing power and radar networking. Since computing and networking are going up exponentially we may find that the F-35 has a much shorter useful combat life than the F-16. True, they’ll see the F-16 coming, but then the usefulness of all combat systems is in the strategy with which they’re used. A World War 1 steam powered destroyer might still contribute to a battle if it was used within its limits and for purposes where it can do the job. Similarly, there may still be a place for propeller driven air support. But planners and politicians always try to get the most sophisticated, sexist, expensive thing they can.
F 16s are a cheap alternative to other planes like the Eurofighter or the F 35. Bang for the buck. The danger for poland is growing as the Russians show in the Ukraine.
There remain many things to do in Poland regarding security. BUT - The biggest problem stays the Polish (European) dependence on Russian energy and not millitary questions. First of all Tusk should convince Merkel to let remain the German nuclear power plants working (because of some imbecile green dreamwork it is planned to shut all of them down in 2022). Furthermore the EU needs a energy plan and reliable structures to get independent in case of a Russian energy embargo during Winter. This only can work, if the countries in central and west Europe work closely together. There is more than enough coal and gas in France, Poland and Germany if modern technology to tap new energy resources is used.