Pragmatic describes the willingness to do something in spite of the disappointing expectations:
1 Dealing with things sensibly and realistically in a way that is
based on practical rather than theoretical considerations:
a pragmatic approach to politics
Cynic describes that sense of hopelessness:
1.1 A person who questions whether something will happen or whether it is worthwhile:
the cynics were silenced when the factory opened
Should this person be called a cynic or a pragmatist? It is hard to choose between the two, but since this is a single word request, pragmatic seems to embrace the notion of cynicism sufficiently. Pragmatists understand the limits of a situation and simply do what they can to make the most of it.
Together, the two words make a great team. For his noble efforts to keep the ethnic tinderbox of Europe at peace in the early 20th century, the statesman Klemens von Metternich was honored by Arnold Blumberg with the label of pragmatic cynic:
The splintering of Central Europe, and the creation of so many
nonviable states since the war, may give us renewed respect for the
pragmatic cynic whose name is forever associated with the years
Great Leaders, Great Tyrants?: Contemporary Views of World Rulers who Made History
As Plato is said to have said:
The penalty good men pay for indifference to public affairs is to be
ruled by evil men.
Congressional Record, Volume 98, Part 6, Page 7944
John Stuart Mill concurred:
Let not any one pacify his conscience by the delusion that he can do
no harm if he takes no part, and forms no opinion. Bad men need
nothing more to compass their ends, than that good men should look on
and do nothing.
Rectorial Address Delivered at the University of St. Andrews