I was looking up ticket prices on the Titanic, and the price difference between First Class (parlor suite) £870/$4,350 ($83,200 today), and First Class (berth) £30/$150 ($2975 today) is shocking. What was the difference between the two? $83,000 strikes me as an absurd price for a trip, especially given that there was another luxury accommodation available for about 4% of the cost.
The suite has two bedrooms, a sitting room, and a private bath. The berth is potentially shared with a stranger on the way over, is a single room, and you have to share a bathroom with everyone else.
I suppose once you are at a certain level of rich, you might as well spend more money to be comfortable.
Even today, if you want to cross the Atlantic in the most luxurious cabin on the Queen Mary 2 you will be paying up to $40k per person. A very nice, albeit more pedestrian, cabin on the same ship goes for around $2k per person.
According to this site, the voyage was intended to be almost six days.
Meals were included. As you can see here, meals for first class were appropriately elite.
There were three times as many second and third class passengers as there were first class tickets.
There's a reason, besides the loss of life, that the Titanic remains in the public consciousness. It was sensational. First-class was not upper middle class, they were millionaires paying for the experience of this maiden voyage.
Looking at it from a business and economics standpoint, a seller will make the most money by charging the maximum that a person would be willing to pay. Different people have different maximums. If you offer a variety of services that cost the maximum that people of different incomes are willing to pay, you'll increase profits. By designing suites and services at a level of luxury to please the wealthiest, you're getting the most value out of them. Regular first class is a big step below that--it's really not even in the same class. But calling it First Class is savvy because the ordinary wealthy wouldn't want to use lower than first.
Income inequality. The very richest of society had immense wealth compared to everyone else.
British society was marked by a huge degree of inequality between the richest and poorest. The top 1% owned 70% of total wealth, and top 10% owned around 90% of the total wealth. £160 per year was the annual income at which income tax became payable, and considered to be the dividing line between working and middle class.
Here's a story about income inequality with a graph. The graph shows that income inequality was at a peak around 1912.