The following is taken from the Wikitree mission statement:
We privately collaborate with our close family members on profiles of modern people. As we go back in time, the trust circles for ancestor profiles grow wider and wider. Collaboration on deep ancestors is between distant cousins who are serious about genealogy.
Because all the profiles are connected on the same system the process is creating a single family tree that will eventually connect us all and thereby make it free and easy for anyone to discover their roots.
I'm not sure what you have noticed on the profiles you have entered so far with regard to enhancements to them by others, but you will probably notice additions to them & merges as you enter older ancestor profiles into Wikitree.
Of course you can work on a desktop genealogy application in order to further your family tree (I do). However, if you agree with the Wikitree mission statement to help create a single family tree connecting us all, you will want to download that info (via GEDCOM or manually) to Wikitree.
I'm not sure, perhaps what we might like to see is an easy means to view progress on the single tree we are trying to create.