When rabbits get older they get lazier - simple as that. Some have very active personalities and love to explore and will continue to do so into old age, while others pass the 1 or 2 year mark and settle down for extended naps. It sounds like your bunnies are very content to just sit and nap and hang out. Dutch bunnies tend to be known as smart and troublemaking bunnies, but it sounds like yours are just the more quiet and mellow type.
Also, bunnies who have a partner can find it easier to just spend time with their bunny friend and not spend time with people. It can help to really try to bond with them and spend one-on-one time - you can teach some simple tricks, get some treat dispenser balls, or other active toys that will encourage them to interact with you.
Also, bunnies who are free range can be quieter. They don't spend all day waiting to expend their energy outside the cage - instead, they can move around whenever they want, so they're less likely to get out their energy in big displays of binkies and bunny 500s. I'm not suggesting you lock them up more, but it can help explain their behavior, especially in contrast to the bunnies you grew up with if those were caged most of the day.