I think the real reason is they're thinking about opening their foundry to external customers in a meaningful way. A modern foundry is expected to have a suite

I think the real reason is they're thinking about opening their foundry to external customers in a meaningful way. A modern foundry is expected to have a suite of hard IP blocks to drop on a design to cover PPA sensitive blocks like CPUs someone would want, and blocks with analog bits like PHYs. Best way to ameliorate people's concerns is to have shipped a chip that runs with those blocks.