[Overtaxed]

...or is Frodo not a "leader-type" person and Merry naturally is.

[HairOfTheDog]

One of the two... Frodo is on a mission planned by Gandalf. He didn't imagine Gandalf would not be in charge, and when Gandalf didn't appear, he just didn't have any ideas. Merry did. Frodo takes advice from whoever gives it these days, so I am glad that Tolkien set him up with Strider before he could be led astray...