It IS true that not everyone can get six-pack abs THAT ARE VISUALLY APPARENT. Some people have highly defined 8-packs! Some people will never EVER have visually apparent 6-pack abs no matter how skinny they are or how hard they work their abdominal muscles. Don’t believe me? Look at Arnold Schwarzenegger and Frank Zane. Even Franco Columbo’s top 2 abs are SOOO small (due to genetics) that he appears to have a 4-pack. Work as hard as you want. At the end of the day, you can’t beat genetics.
(this is a repost. accidentally commented on your question instead of answering)