Joe,
That may be, but take a careful look at what the ownership at Shawnee must consider.
First, the island floods out quite often damaging the course.
Second, the entire area has flooded out a number of times in the nearly 100 years since it opened in 1911 causing the golf course to have to basically be rebuilt in its entirety as well as repairs to the Inn which also suffered considerable damage.
Third, if a restoration is to be given real consideration, the entire golfing facility of 27 holes will need to be shut down as Kyle correctly pointed out. The reason for the additional nine that was installed was to allow for more member play (the course was/is the home of the Shawnee CC) while Inn visitors could be placed on the other nine.
You ask the question of what are the problems to doing a restoration "Besides the obvious ($)?" Yet the reality is that, at least in Shawnee's case, the $ is the overhwelmingly largest aspect in every single reason given for not doing one. It cannot be separated out in this instance.