The alternative to P3s is no infrastructure.  The public won't accept the tax increases to build new infrastructure that's needed.  And crucifies governments that run large deficits.  There's also ridiculous provincialism in Canada.  For example, consider the reaction if the federal government announced $30 billion for a high speed rail line from Quebec to Windsor.  You could probably hear the whining in Iqaluit.

And that's just on new infrastructure.  The public is also vehemently opposed tolls and fees on existing infrastructure.  Kathleen Wynne shooting down Toronto's mayor John Tory on road tolls to repair the Gardiner shows how bad the situation is.  The public won't tolerate $2 tolls on a crumbling elevated highway.

There's only one way out of the bind for governments, resort to private capital.  If you wanted all infrastructure to be publicly funded, ask your politicians for major increases in taxes.