The 500Wh packs are often in the 13-15 Ah range each, though, so two might be a closer comparison. What's the Wh rating of this infamous 30 Ah pack of which you speak?
Since I sometimes can pre-seed a route with batteries (leaving them with friends, relatives, and with businesses I have a connection with), that's an advantage to the 500 Wh/14 Ah packs that are available for my current e-bike. That way I'm effectively getting increased battery capacity without having to carry as much weight.
I suppose if I had to choose between carrying a super-heavy pack everywhere (even for short rides), or having the flexibility to use a lightweight pack for small rides, I'd go with the lightweight option (even knowing that it would mean carrying multiple packs for super long rides).
I started with a 55 pound e-bike. Then I upgraded to a 49 pound bike. Now I've upgraded to a 42.5 pound e-bike. My next bike will probably be 33 pounds. I don't think I'd be willing to accept the weight penalty that comes with converting a bike (which also voids its warranty) and putting on a massive battery. All too often that puts you in the 60+ pound range, and I don't think I'd enjoy pedalling a bike like that.
It's also not what I need most of the time, since super long trips that need a super-huge battery are a relative rarity for me. My day-to-day riding is mostly relatively short trips, and a lightweight bike is more enjoyable for that.