Of course it isn't and you would be naive to expect it to be! In a 4 years there are technology advancement made possible that weren't before and the latest OS always takes advantage of the latest technology. And to be honest I don't miss any of the features left out of iOS 7 on iPhone 4, they are not a dealbreaker for me (maybe airdrop but since I can't use it yet with my mac it's a bit of useless)
Things like Siri not being available for the iPhone 4, Apple said some rubbish about how the Microphone on the 4 wasn't clear enough for Siri to understand you, which was odd considering the siri app worked fine on it, and after jailbreaking my old 4 it ran Siri just fine. When old Android devices got updated to 4.1 they all got Google Now, they got every feature 4.1 brought.
I'd say he ignored your "point" because it's ridiculous. It is unreasonable to expect a 4 year old phone to do everything a brand new phone can do, and so to state that it "isn't the full OS" is inflammatory trolling garbage. You make it sound like Apple is taking away critical functionality, but that couldn't be further from the truth. In reality, new phones get all the new stuff and old phones get only some new stuff; it's a win for everyone.
I'll give you this one, as dropped Safari tabs is one of the biggest reason to increase iPhone RAM, but you're making it sound like you have dozens of examples. I only see one.
I didn't say I had dozens of examples, I said I constantly ran into problems because most of what I did on my phone outside of messaging, was use the web browser. I also disliked having apps I like open being binned from memory, obviously this got better as I went from 128, to 256, to 512 and finally 1GB of Memory for phones. But I really think 2GB should be the sweetspot for now, Android has been on it for a while, Blackberry 10 went onto 2GB of RAM. Even the flagship Windows phones have made the jump to 2GB, and windows phone runs buttery smooth on low end hardware. I would hope iPhone makes the jump to 2GB soon.
I point out these updates lacking features on older phones because its the first thing people mention in relation to Android updates. Bragging on about how their phone runs "the latest version". I feel like saying congratulations, your version number in settings has a higher number, but almost none of the features. Android phones may be slower to update, and quicker to abandon old handsets, but when you get a update, you get everything.