Almost all the companies in SP500 are losing their market breadth to the top 10 tech companies driving most of the value gains. They are so big now a 10 percent increase in their value drives 4% overall gain in the index.
The index is not a good buy anymore because investment is going to SP490 and SP10 in 60:40 ratio.
$NFLX is down 43% in the last one year. Result of both liquidity going to AI and bad overall economy are the reasons.
Valuations matter and they always do. Still expensive at ~22x trailing PE.