Only opportunity is infinite.  Everything else you need to do to run and operate your business is limited in some fashion.  Your business plan should anticipate scarcity of resources.

Some resources in the world are non-renewable.  If you use them up, there will be no more.  You have a social responsibility to use only what you need, to save these resources for others who need them more (including future generations) and to seek out alternatives so that you don't have to use these resources at all.

Imagine your business a 1,000 years from now.  If it lasts that long it will be truly sustainable.  Consider what you need to do today that makes your business valuable forever.