It is not clear why “Impeach Obama” is no longer part of the name or the above logo of this group, but it is much easier to raise money from anonymous donors as a non-profit organization, if you are not about impeaching Obama or removing him from office. A 501(C), non-profit organization is not allowed by law to be principally about politics.
Overpasses for America was originally called “Overpasses for Obama’s Impeachment.” Then they changed the name to “Overpasses for America” with “Impeach Obama” as a subtitle on the logo. Now “Impeach Obama” has been dropped altogether from the logo. They are obviously moving the emphasis gradually away from impeachment as their principal goal to something broader and more vague.
Of course, there are people, who will pay to stop an impeachment movement and divert it to something else, more sedate. Even many wealthy Republicans do not support an impeachment effort. The big money is not behind impeachment and removal of Obama. It is easy to buy off an organization that is centrally controlled. To be successful, a large impeachment effort will have to be truly grassroots and not come from one, centrally-controlled organization that may be influenced by wealthy contributors.