If I wanted to buy a small amount of bitcoin, self-custody, transact with it today, and I'm rational, I would pay a premium that's at least equal to the amount of fees I'd save not having to touch the chain.
Well, I would be willing to trade several dollars higher for LN-BTC than mainchain BTC right now, so perhaps.
It is vital to differentiate between premiums and differently priced tokens though. You already pay premiums for some LN exchanges like RoboSats. Nonetheless, it is the same token. For BTC to really become two-price, we would need to start considering them different tokens. Because the market is unlikely to ever do that due to the 1:1 mapping of LN-BTC and BTC, we may see premiums but not a two-price situation. Subtle but imho important distinction.