Parking is not the be-all-end-all solution (proper bike lanes is also crucial, and showers/lockers are a requirement for an additional subset of potential bikers) but obviously it helps lower the barrier to entry for enough people.

Portland and New York are not every city, they have unique problems that other cities do not have. In most cities bicycle theft is not as serious and merely improving bicycle parking does not necessarily get rid of the theft problem entirely. In the vast majority of cities the biggest roadblock to bicycle transportation is the roads. There is simply nowhere to ride except on the same roads that carry heavy vehicle traffic.

Bike theft is highest in places where bike transportation is already very popular (figure out why this is so), solving the bike theft problem is a 2nd order problem that most cities do not face because they haven't yet solved the 1st order problem of making it possible for anyone but the most committed to commute by bicycle.

Also, I should note that I've lived in several cities in 3 different states (Oregon, Washington, and Alabama) where a bicycle was my primary form of transportation, in every case parking was never as big a concern as just getting from point A to point B safely.