Welcome to the forum, CurrentRide.
I understand your frustration. As others have pointed out, there was a lot of this sort of confusion and disappointment when the Model S came out.
I would encourage you to express your concerns directly to Tesla in the most clear and constructive terms possible to muster. While they often do not show that they are listening, they usually are. Model S went through MANY iterations of pricing and bundling and unbundling of options while Tesla learned the shape and dimensions of their nascent and expanding market. They cannot offered to turn away a lot of early reservation holders.
Personally, and this is just a hunch, I think the delay for the non-P90 cars will be shorter than stated. I recognize that they have always felt they had to front-load the expensive configurations. This time, they are at least stating it upfront, whereas with Model S, those of us here had to discover it on our own. But I suspect they also are stating the nearly-worst-case scenario (timing-wise), accounting for very heavy buy-in to the P90 AFTER the signature series AND a continuing modest pace to the manufacturing ramp. If either or both of these assumptions does not play out by the end of the winter, I think we could see 90's delivered by early spring and even 70's by early summer.
Just my humble opinion.