What primary environmental factor causes variance in published supernova rate estimates for the Milky Way?

Interstellar obstructions like dense dust and gas clouds in the galactic plane blocking views.

The uncertainty surrounding the true supernova rate within the Milky Way is largely attributed to observational bias caused by the structure of our galaxy. The solar system resides within the galactic plane, which is densely populated with gas and dust clouds. These interstellar obstructions effectively obscure the view of many stellar deaths occurring deep within the galactic disk or behind the central bulge. Consequently, current surveys primarily detect events that are relatively close or occur in directions where intervening dust is thinner, meaning many true stellar deaths remain invisible to telescopes until their effects interact with surrounding material, potentially years later.