Sure you do! So do I! You and I probably live in the most expensive 1% of places on the planet. We live incredible lives - our existences are better on average than anything any king had 150 years ago. We have whatever food we want at whatever time in the year we want it. We have phenomenal connectivity and mobility and, if we need to be on the other side of the planet in 48 hours time, that's doable.
Of course, I want more. The guy next door has a Range Rover and a Porsche. But I know there are literally billions of people who cannot imagine the luxury in which I live.
The gargantuan difference between kings of old and us today, the critical difference that these comparisons always miss, is that whatever lifestyle you choose, you have to work roughly the same number of hours to maintain it.
If you are a programmer, you can't just decide to work 10 hours a week for $25k and live a $25k lifestyle. If you want to earn $25k, you'll probably still have to work full time to do it. Regardless of the comforts we enjoy, we are still slaves to the workweek (there's not enough contract work for every programmer or designer to go freelance), and that is why it's right to complain.
We may have more "things" per person than Arthur himself, yet we lack the freedom and status of being royalty.