Quantum had a decent article addressing sail life. They break it down into two categories - shape life, and structural life. Sails will lose their shape long before they reach the end of their structural life and are no longer viable sailcloth. Unless we're replacing sails every few years or less like avid racers, most of us are sailing with sails that have lost some or much of their shape. That's not always much of an issue as we accept the inability to point quite as high, or sail as flat as we did when the sails were new. But at a certain point before structural life is reached, furling mains become a real issue when they lose enough shape and the belly negatively affects smooth and efficient furling. This is both frustrating, and potentially a safety issue if you need to quickly furl the main as a gust front preceding a thunderstorm starts to blow through.
The OP did the smart thing and took the sail to a loft, given the age of these sails is over 2 decades (OP said original sails and hull was built in 2001), and the other issues he's experiencing. I'll just close by saying I bit the bullet last fall and replaced the original sails on my 2009 H36 and couldn't be happier with new radial cut sails. Quantum did a great job at a great price. I'll be selling my still structurally viable sails as there's always someone not yet ready to plunk down the boat units for new sails. I'm definitely enjoying a boat that sails noticeably different than it did last year. Good luck to the OP.