Like the early Signature cars, those owners taking early deliveries paid more than owners purchasing cars later.
While the P100DL costs more than a P90DL, it's not clear Tesla will end up charging a lot more for a 100D than a 90D.
And, they may decide to offer both a 90D and a 100D option for a while.
If Tesla decides to drop the 90, then they really will need to get the 100 pricing down to around today's 90 pricing, like what was done previously between the 85 and 90s.
Tesla has really done a pretty good job in keeping pricing down. When I ordered my P85 4 years ago, the price I paid then, is comparable to what a 90D costs today - with about the same performance and many new features (AP, TACC, power folding mirrors, parking sensors, ...). If Tesla ends up dropping the 90 - and only offering the 100 battery packs, if they also increase the price, they may meet market resistance...