What would have happened to the Winchesters if s1e1 had never happened:

• Sam would have had a white picket fence, a wife and kid, grew old without his brother, and never worried about hunting again.
• Dean would have died young and without a partner or kids due to a hunt gone wrong

What happened to the Winchesters after 15 years of character development:

• Sam had a white picket fence, a wife and kid, grew old without his brother, and never worried about hunting again.
• Dean died young and without a partner or kids due to a hunt gone wrong

Do you see why fans are pissed?