I am sorry brother, but you will get the Permanent Residency to "Canada" because that province agreed to let you in. I mean there are other ways, but this is the easiest and that is why we took this route, yea? Also, Permanent Residency has always been temporary, that is why it's not called Citizenship and in some cases where they have revoked Citizenship even, I am afraid even that is not permanent.
Also, regarding your point that Ontario will be full with Immigrants if such controls are put in place, I'll explain it with numbers. From 2005 to 2009 only 1247 people were nominated by Ontario compared to 13089 by Manitoba and 4155 by Saskatchewan. This is because, Ontario already has a lot of immigration from Family Reunification, FSW and Marriages, hence PNP was put in place so that more people could come to these provinces with lower immigration and help them grow. For example at this point Ontario can nominate only 1000 people every year compared to 5000 by Manitoba and Saskatchewan.
Moreover, I do not know about you but when I filed for PNP, I wrote so many things to Province of Manitoba in my Letter of Intent about how I will make sure that I live in Manitoba and help it grow and boost. I will pay taxes to Province of manitoba etc etc...and then they Nominated me. If I was to leave than what happened to all my promises that I made to Province?