1.5% of a big number is still a big number. Western Digital's revenue in 2018 was 18 billion. Even if only 0.15% of their revenue went to ARM, that would be 27M

1.5% of a big number is still a big number. Western Digital's revenue in 2018 was 18 billion. Even if only 0.15% of their revenue went to ARM, that would be 27M or enough to hire 100 chip designers at 270K each. That would be enough people for a very advanced chip, but WD doesn't need to build the next supercomputer. Instead, they want a chip customized to handle their specific workload with high throughput and probably some specialized instructions to put some algorithms in hardware. Moreover, their RISCV chip design expense should reduce over time both because they don't need to change chip micro-architectures very often and because as more companies switch to shared, open hardware, the costs are reduced Another example is Nvidia. They continue to hold an ARM license for several ARM designs and another license for their own custom Denver/Carmel designs. Despite this, they still opted to use RISCV in their GPUs. These companies manufacture chip designs for a living. They certainly understand the costs involved and have determined the immediate and long-term costs are lower vs the provided benefits.