This is true, read my top level post for more information. The Ariane 6 is basically an evolved version of what was the Ariane 5 ME. Many of the things that ar

This is true, read my top level post for more information. The Ariane 6 is basically an evolved version of what was the Ariane 5 ME. Many of the things that are now Ariane 6 were developed for Ariane 5 upgrades. The new upper and lower stage engines are both just upgraded Ariane 5 engines. However they realized they could never compete with the Ariane 5 core against Falcon 9 (in 2014) they changed some political design processes and made the rockets more flexible. The most relevant difference between Ariane 5 and Ariane 6 is that Ariane 5 always had to huge solid boosters, while the Ariane 6 has 2 or 4 depending on the mission. That makes is possible for the Ariane 6 with 2 boosters to be in the competition for LEO missions. Something Ariane 5 wouldn't have been able to do. But you are right, the 5 billion $ it cost to develop Ariane 6 will required it to fly for decades to make it worth doing compared to Ariane 5 ME.