Besides the environmental issues, from water allocation to pollution and littering, tourism has led to cultural decay, largely thanks to tourists disrespecting local populations and their religious sites. If tourism was cut back, Bali could save its cultural identity while also propping up its economy through marine and agricultural industries. This is not a zero-sum game.
Balinese culture has sustained and even integrated itself with foreign visitors for almost a century. As children continue to learn traditional worship, dress, and art, they also monetize their culture by performing for and selling merchandise to tourists. As long as local populations are able to maintain their traditional lifestyle on their own terms, tourism shouldn't be a problem.