Is that a requirement? Let say a big startup announces to cease operation with hundreds of paid customers. I think it is totally acceptable for a short announce

Is that a requirement? Let say a big startup announces to cease operation with hundreds of paid customers. I think it is totally acceptable for a short announcement like Mapzen’s, but with a seperate page about migration and refund. Then the next is making sure everyone in the company will help taking customer calls. Unless stated otherwise, I think we can assume whenever a company goes out of business, the reason has to be $$. There are special cases like political pressure etc.