The Frenchman spoke out after the defeat of the Reds by Real Madrid.
"This is the end of an era. They conceded too many goals against Brentford, Wolves, and Brighton, not to mention the last match against Madrid," said the Arsenal legend.
I wanted to understand what they were now worth and saw a fragile team. They led 2-0. It's precisely the kind of start you want against a Madrid team or any other team in Europe at Anfield, and they couldn't even keep that.
Yes, Alisson made a mistake, but he was not rescued. Thibaut Courtois is wrong - but Real Madrid is a big team, and they helped him.
Some things need to be changed. Jurgen Klopp doesn't need to go, but some players are no longer at the level to play for Liverpool. It happens to the best; it occurred to me. This is the end of an era.
When I see a guy like Luka Modric at his age get the ball and break through midfield like it wasn't there, pass the ball to Vinicius, and Vinicius pass Benzema...
The Reds are not doing well right now, so they must reinvent themselves and keep their heads up for the rest of the season."
Henry also compared Liverpool to Barcelona in 2008.
"I can remember my time at Barça. My first year at Barcelona was also the end of an era. We had the best players on the team, but we didn't win anything.
"A year later, a new manager, Pep replaced Rijkaard - I'm not saying Liverpool should replace Klopp - but new players came in, and then we took the treble."