It depends. If enough people end up transacting through off-chain implementations, these fees might not end up being as rewarding as you believe they will be in the future. Sure, there will always be a decent level of demand for block space, because that's what you need when it comes to off-chain implementations such as Lightning Network, but I am a bit more reserved in this case. In your scenario, it will mean that the majority of the people will still continue to transact on-chain like they do now when sending Bitcoins back and forth. Either way, there is no way to find out for us what's exactly going to happen, because we're not here anymore by that time.