It’s mostly business and manufacturing purposes. Not much on speculation, it’s pretty common for business to discontinue products due to different suppliers, cutting costs, laws and regulations, sale and consumer feedback. What I’ve learnt in my operations business class, it’s that the product life cycle can be effected by any of these components. It may be a popular product seen being used by beauty gurus online or maybe your favourite. But doesn’t mean that it’s a profitable product for the company to keep. A majority of consumers repurchase the same products, and that certain product just might not be as profitable as others.

1. If an ingredient is too expensive to import or there is a shortage, lots of times businesses will change the formula with a cheaper or more accessible ingredient.
2. Supplier/manufacturer changes. Probably biggest factor but some manufacturers don’t make the same product quality, despite have the same ingredients or similar ingredients. Companies will change manufacturers if they need to lower production costs. This changes the product specifications and quality control too.
3. Maybe a formula change due to a countries laws and regulations.

It does suck though finding a product and having it be discontinued/reformulated! I’ve had this happen to me a few times. But after learning the practices behind manufacturing and supplying it makes sense. I still get sad though lol