The CPUs of modern console are pretty standard general-purpose CPUs: the PS4 and XB1 use customised AMD APU, and the Switch uses a Tegra X1. That's not useful for supercomputers.

The PS3 was using a pretty weird CPU, which importantly had a single general-purpose core but 6 SIMD co-processors, making it very useful for compute tasks on supercomputers.

These days you'd use off-the-shelf compute-oriented FPGA or stream / GPGPU units paired with general-purpose CPUs e.g. OLCF-4 has 9216 general-purpose CPUs driving 27648 Tesla V100.

Also, console makers collect fees from third-party game publishers, whether it's on physical media or it's downloaded. I don't know how much profit comes from each source.

Most people have been saying that consoles are less subsidized now than they used to be.