Theoretically, more cars can fit on a given block if spaces are not laid out, since the spaces in question would need to be rather long to accommodate larger vehicles. This is the same reason no delineated spaces exist on streets such as Exchange where multispace kiosks have replaced single space meters. If anything, more cars on a metered block would mean more meter revenue, so it would be in the City's interest to maximize the number of cars.
Beyond that, there would be the added cost and effort of maintaining the painted lines, and the fact that they would be useless as soon as there was snow on the ground. Enforcement would be nearly impossible even on a good day, but without it the lines would be meaningless.
We do appreciate your input, but do not believe the status quo would be improved upon by adding painted lines.

I do not believe that a 15 minute shopping trip or hour dinner on Exchange St is directly comparable to overnight residential parking. In addition, Exchange is a relatively short street with many breaks in it, making it fairly obvious how many cars can go where. The side of Park Ave that runs along the Oakes, however, runs unbroken for blocks at a time. If one car parks inappropriately it can cause everyone else to be misplaced too. While it's true lines will fade and be covered by snow simply making people aware of the need to consider the amount of space they're taking up could help remedy the problem without enforcement of any kind. And finally, it would not be in the city's (financial) interest at all since the spaces in question are not metered.

I agree with kready on this issue you could have spots made for all size cars trucks etc and nicely painted
and those who chose not to park properly would keep right on doing so.
it happens all the time in the west end.
i also agree with you BikeMe but sadly no matter what the city did we would have parking problems until all parkers learn how to park properly and that will never happen i have lived in Portland for almost 40 years and have seen many bad parking jobs:)

I think I was unclear. The point I was clumsily trying to make was, if we have removed the individual space markers from a street where a revenue advantage exists to maximizing the number of parked cars, then we must be confident that this is the best way to maximize the number of parking spaces in the long run. I realize there is no metered parking on Park Ave, of course, and I recognize that there will be times when certain cars park in such a way as to prevent the most efficient use of the space, but overall more cars can fit on a given block if they are not forced to use parking stalls.

Well said kready:)