What does the year have to do with anything?
Macs have been capable of complex folder operations since the beginning as well, if the
appropriate utility is employed. Using a drag-and-drop file browser to initiate such operations and expecting it to handle all possible contigencies correctly is naive and unrealistic. Just read the man page for
rsync sometime to see what sort of options one may need to consider. An occasional brain-dead merge may be handy once in a blue moon (such as when their contents are unique), but that isn't enough to warrant providing the function in Finder. The need for this is typically very
seldom. And I
contend that: if someone frequently does encounter that need, then their workflow would be enhanced by using an appropriate program (either a click away or scheduled automatically, and properly configured for the task at hand).
The fact that users are expecting this behavior merely illustrates that they have no real appreciation for the range of scenarios wherein a 'merge' produces improper results. They more or less have accepted it being available without really giving it that much thought. The feature does have its place, but Finder isn't that place. This is about a
philosophy... so the "year" 2010 is insignificant.