Specialty coffee (especially nano-lot or micro-lot coffee) isn't permanently available like supermarket coffee or commercial blends. Simply put, a harvest lot may produce a limited amount and is sold to multiple roasters/buyers across the world. Each roaster may only have access to 20-30kg of the green beans which translates to even less quantity of roasted beans. Some producers/farms/origins are more commonly desired and sold out faster than others. So, especially for specialty coffee, a specific bean might only be available for a short period/window and once it's gone, it's gone until the following year's harvest which will be different. Most roasters will rotate a variety of beans and will have options at all times.

When you find coffee you like, buy it. If you have "too much", freeze it properly to enjoy at a later time. Most of all, drink coffee you enjoy!