Same reason why they are not an investment bank investing in stocks, or building skyscrapers in Dubai.
It's not their business. They've built over the many years, a very defensible business out of expertise (and IP). That expertise is unique and resilient to the whims of a speculative investor hive-mind.
More practically, they just wouldn't be able to compete. Against companies that build ASICs specifically for mining, the tech they have, while is viable for the small-time gamer-miner demographic, does not have good returns on a larger economies of scale.
It's not their business. They've built over the many years, a very defensible business out of expertise (and IP). That expertise is unique and resilient to the whims of a speculative investor hive-mind.
More practically, they just wouldn't be able to compete. Against companies that build ASICs specifically for mining, the tech they have, while is viable for the small-time gamer-miner demographic, does not have good returns on a larger economies of scale.