This is something many of us have said on this forum for more than 10 years. Manufactures do not want it, it would appear. The founder of Zero Motorcycles, Neal Saiki patented a pack with replaceable cells back in 2014 or 15. He intended to launch a new ebike, but that fell through. I had invested in the crowdfunding, but when Neal pulled out, most of us backers did as well. Now with most governments beginning to require UL Listing, I don't think packs with replaceable cells will ever be legal to sell.
As for battery packs for bikes. I have a buddy who owns a 2017 Haibike, with the Yamaha system. Back in Spring '24 he was able to buy a Yamaha pack at a Giant dealer. This dealer never sold Haibike or Yamaha branded bikes, but due to Giants using a Yamaha system, they were able to order a battery for him. You are probably safe for parts, for years to come.