Of course they tried cricket in the Olympics before - France and England were the only ones with a team then and the single game lasted two days…
http://en.wikipedia.org/wiki/Cricket_in_the_Olympics
The French team consisted of British living in France, so really it was British against British…
The Olympic sports are decided on historical significance, financial obligation to put on the event, time it takes for the event, popularity, and spectator draw. The last two are basically the same. This is why Three Day Eventing changed to the short format - they were almost kicked out because the sport is not all that popular, takes a while and the financial cost and space required were very prohibitive.
Golf - almost every country has a golf course and if the course is changed or a new course is made specifically for the Olympics, it can be used again.
With the Equestrian sports, for the events that happened in the arena, the race track had to be converted and will need to be changed back to a race track. The cross country course needs to be turned back into a golf course - there really isn’t any reusable options. Olympic stadiums? Some are monuments, some host other games and events. I have swam in an Olympic (not Olympic sized, an actual Olympic) pool before. I have yet to see an Eventing cross country course continue to be a course after the Olympics - enlighten me if I am wrong.
Soccer (football), as far as I know, is much more popular worldwide than baseball. While it does not take up nearly as much room to play, both baseball and softball are slow moving games that take a long time to play. Football is one hour - not 9 innings that may take 2 hours or 10 hours.
As far as synchronized swimming goes - you try holding your breath while staying in unison with a bunch of other people for a minimum of what 30 seconds they are underwater at a time?