Chrome, Safari and Edge are ~80% of the web's browser. It's mental you don't support them.
If Silverlight is no longer relevant, that should be enough of a hint to drop it as your delivery engine. Netflix and Amazon Prime don't use it - why should you?
Even if it worked, it's a really bad choice - Silverlight CRIPPLES even modern hardware. On my (latest model) Macbook Pro, the fans start spinning full pelt and CPU usage hits 100% trying to watch anything on Silverlight on Firefox.
I try to watch 'native' when I can, but usually I only grab a few minutes here and then viewing time when I have my Mac laptop in front of me, so this means relying on a web browser.