
Keep in mind, that Amsterdam is possibly one of the world's most famous cities for transit, but it's not the trams that earned it that reputation: it's bicycles. The city is the most bicycle-friendly place in the world, and it goes without saying you haven't experiences Amsterdam until you've spent an entire day on bike.
The tram system actually reminds me of a significantly enhanced version of the Toronto streetcar, with an intense network of mostly linear tram lines:

[Might have to open the pic in a new window to get to see it] So it's amazing that a city of about 800,000 people has all of these tram lines (granted at any given time tourists clearly outnumber locals). It's also amazing that it supports this in addition to a highly-developed underground metro system, commuter trains to other close-in regional cities, elevated rail similar to Chicago (they call theirs "the tube"), the bicycle-centric focus, and even the canals and River Amstel serve a transit function. It's truly a transit city. Not to mention so many areas in the Centre Ring are pedestrian-only.
I think perhaps all of these modes of transit have grown up around each other. At first it might appear to be a lot of competition for ridership--are the Dutch really that "on the move"? But then you realize, the simple fact is that having a car in Amsterdam is a nightmare! I saw it first-hand several times in the Centre Ring, and never more than when I saw a taxi trying to squeeze in with the bicycles and pedestrians through a crowded bridge a block from a busy weekend market in De Jordaan. Cars in Amsterdam simply go against the laws of physics.
Now obviously, this is not the case in any American city except perhaps NYC, and even NYC is packed full of too many cars. But the point still stands: there is no competition for ridership in a true transit-centered environment, as long as the different modes of transit each serve a real purpose. If Amsterdam was not the bicycle haven that it is, would the tram system be as well-used? Probably not. Would the commuter trains or even the inter-city trains to Den Haag and Utrecht be as heavily-utilized? Probably not.
Lesson that OKC can take from Amsterdam: In order for big-time streetcar utilization to work successfully, grow as many different complementary modes at once. This is why Project 180 coinciding with the streetcar timeline is actually an enormous opportunity, not a duplication of efforts. The city needs to do a lot to expand basic walkability and human access, including a real bicycle strategy that doesn't just involve the system of scenic park trails. That's not really what we need...
I see no reason OKC couldn't use a system of bicycle roads. Bicycle-only intersections, even bicycle round-abouts. Special bicycle lights at each intersection, some busier intersections even with dedicated bicycle left-turn lanes. Or at the very least, sidewalks on every street, that are actually usable. That would be a good start, even if it's just in the inner city! Perhaps I'm getting ahead of myself here and forgetting just how many 100s of years OKC is behind other cities in terms of basic sidewalk infrastructure. It is beyond embarrassing.
One great phrase you will never hear in OKC: Lekker fietstocht!