It all gets rather complicated because the shift from the first "punk" bands to offshoots in hardcore and post-punk and metal subgernre all happened in a very short span. The Ramones first album came out in 1976 and within the span of just a few years, "punk" had already taken many new forms. Hell, Pere Ubu was making "post-punk" in the late 70s before some albums we would consider classics of the punk genre even came out (The Modern Dance predates London Calling by a year and their first single in 1975 predates even the Ramones). Black Flag had already pioneered LA hardcore and then put out the first Sludge Metal album in 1984 while many hardcore bands were just getting started, and a couple years prior, bands like Minutemen and Squirrel Bait were starting "post-hardcore" while at the same time Bad Brains were putting out classics of regular old hardcore.

All that is to say, new genres were starting before their "predecessors" had stopped developing. I'd agree with you that Television isn't proto-punk. It's post-punk, even though it came out during punks heyday. It all changed so fast it kind of blends. Which is why it's easier to classify based on sound than time.

I would consider The Modern Lovers self titled album to be proto-punk even though it came out in 1976, the same year as the Ramones self titled (a true "punk" album) and the same year as early Pere Ubu stuff ("post punk").