1. This is the case for all new technology it will always get cheaper later. I have no problem paying the same amount for a phone each year, but Apple has been inching up the entry level iPhone device every 4-5 years by $50. An entry level 8 retails for $699 vs. the original iPhone at $599. I'm not comfortable paying almost double the price of the first iPhone. It's also more of a value proposition. If the X had the same true screen size, as good battery life, and no other compromises from "upgrading" from the 8 Plus, I could perhaps justify the $200 price increase. Unfortunately, that's not the case. We're on the same page that the technology in the X will become mainstream and therefore more affordable in the future.
2. I'm sure there will be inventory issues but that is the case with every iPhone of late minus the 8 because people are waiting for the X. I fully expect that I will have my X in the first week of release. What you expect has no correlation to reality. There are always inventory issues each year with the launch of the iPhone, however this year there are documented shortages that fall into the worst-case scenario bucket. Let's not forget some customers that ordered immediately at launch last year were still met with 3-4 week delays, for a phone that was virtually the same as it's 2 predecessors. It's so bad for the X this year, they pushed the release date by more than a month, and recent news shows they still haven't started production.
3. You state that it has no real improvements but in reality what you mean is that the improvements don't add value for you. I consider Face ID an upgrade, I consider a larger HDR oled screen a large improvement, I consider the dual-optical image stabilization to be a really nice upgrade, I consider the front facing camera including portrait mode on the X a very nice upgrade. I consider all of those things in a much smaller form factor to be a huge improvement well worth the extra 200. So your preferences don't determine if there are "real improvements" or not. I don't care about selfies, so the front-facing camera portrait mode is of no value, whereas battery life is important to me. I've never had OIS issues on my 7 Plus, so dual-OIS isn't a value-add for me, because it's fixing a problem I've never had. I agree completely, that each consumer will determine what is and isn't of value to them. I'd rather put the saved $200 into buying an Apple Watch for my significant other. Again, if there were no compromises, I could live with the changes (no Touch ID, but Face ID, etc.)
4. 1 Hour less in internet use and 1 hour less in video playback is probably going to be negligible in real world use, but yes the Plus model will always have the best battery life. That is one of the benefits of having such a large form factor to stuff more battery in. The most common uses for smartphones isn't talk time, but internet and app usage. The iPhone X is in the exact same league as the 7 and 8 (non-Plus models) with respect to this battery life. Maybe it's not material to you, but 1 hour is a big deal to me. Anyone with a Plus knows battery life is a night-and-day upgrade from the non-Plus model in real-world usage.