And running the marathon is just running the marathon? I disagree. Big part of running the marathon is in the preparation. Weeks after weeks of training and not skipping a single session. The marathon itself is the tip of the iceberg; important but not the whole "thing".
It depends on your thing. If the marathon was just the motivation, your thing is running... if the marathon was the bucketlist item, it is the thing.
No matter how much preparation and training one does, if they haven’t run the marathon, they haven’t run the marathon.
There are some things that you just can't do without preparation. But never mistake the preparation for doing the thing. You can be "getting in shape for a marathon" forever without ever running a marathon.