That's your opinion. But I've noticed it says you live in Scotrail area. I actually live in the Network South East area and I would almost die if they withdrew First Class!
Curiously, the first area of the country to lose first class on a widespread basis was London, where it was withdrawn on all services operated within London in 1940 due to wartime overcrowding. It was never reinstated afterwards, although integration of stock has later led to loss of clarity (which it seems continues with the new Thameslink stock).
The rest of the country did it spasmodically, PTEs generally tried to get rid of it, and when Provincial came along to the rest of the country they had a good go as well. Some has now actually been reinstated by TOCs in recent times, for no actual apparent reason.
From when the Mk2/Mk3 stock came to the WCML they started the overprovision of first class on that route, which built up to the initial Pendolinos which had 4 of the 9 cars first class. There is proper first class fare demand into London in the morning, and return in the evening, four days a week; such demand even drops on Fridays. For the rest of the day and the rest of the diagram, and all weekend, it is really just empty stock.
I well remember the ScotRail Glasgow-Edinburgh high speed push-pull shuttles of the 1970s, one coach of the six was first class, it hardly ever had anyone in it, where the other five were frequently standing. There was an exception. It formed a useful club for those ScotRail management who qualified for first class free passes, there were more of them than now, who used it as a form of private club when commuting between the two cities, as quite a number did. In InterCity days, services from London to Crewe/Derby/York were similar.
I'm sure if the actual revenue per coach was measured, especially as much long-distance first class patronage is advance fares, sold notably cheaper than the walk-up business travellers are paying even in standard, it just wouldn't wash at all. BR InterCity pretended to have a management measure of revenue per coach, but what they did was get to revenue per train and then divide it by the number of coaches, completely masking the first/standard split.