All I can say is it certainly will be interesting how this all plays out. Will it affect the theme park business? It seem to already be a reality for parks in Asia. Here in America, it really depends. It will depend on how bad the virus affects the people and what steps parks can take to step up hygiene for visitors.
When I said "steps parks can take to step up hygiene for visitors", what I specifically meant was will parks provide resources for hygiene like hand sanitizing stations or just something to people who visit the park so people have that option to reduce the risk of infection and/or spreading the virus.
All we can really do now besides speculate is watch the progress of this new virus and put faith in scientists developing a vaccine.
And of course, practice good hygiene whenever possible!