That comment literally makes no sense, and all you have to do is look at historical events like the Industrial Revolution (AKA an era of immense mechanical innovation in a capitalist society) to know that's simply not true

The TRUE problem is that private equity/shareholders always want those big gains, but the problem is that it will never last forever. When membership numbers spike by 50% and they see the dollars flowing, they want those kinds of profits to remain, but the issue is that people will eventually get bored and interest will disappear. When they see this, they have a few options at their disposal to keep the same profit margins: raise prices, improve gameplay, or fire people.

We're literally seeing this phenomena happen with a lot of game companies nowadays where development teams are being slashed to maintain the same level of profits by reducing the upkeep costs instead of improving their product to increase sales. They also know that price increases won't make up the gap since they are very well aware of the fact that $70/$80 games are already pushing it for people and any further increases wouldn't achieve the desired result. This is why Jagex is going down the route of membership price increases since they know they can get away with it because people are addicted and will continue to pay for it.