If you want more optimized games buy games on a console. There's a great chance of optimization on those.
I don't have a console, but I that's what I thought a few years ago, when games were specifically designed for a console. These days, games are made to target PS5, Xbox, and PC at the same time, with the same code. Graphics engines like Unreal use that versatility as a selling argument (they even support mobile devices).
Here, the console versions of DD2 don't seem very performant.
So I don't believe this is always true today, except for games that are made for console first and ported to PC later, or when it's carefully optimized for console because, as you said, there's only one configuration to test.
Then there's the matter of what workload it is performing. How exactly can we know what it's performing and if there are better ways of doing it. Nothing is performed in a vacuum. It's always pros and cons. If you optimize something, you'll lose on something else. There is no free lunch.
It depends. Writing optimized code takes more time and skill, and it's more difficult to maintain later, so programs are often sub-optimal. There's almost always a solution to make it do the same task with less memory or less computing power, given enough time to think. There are tools to help with that, too (profilers). It can be a free lunch for us, but not always.
In this case, they have data to transfer when objects come within viewing distance. When too much of it happens at the same time, the CPU struggles. They could reduce the quality (number of objects, or details per object) or stage the objects by priority, spreading the traffic over longer periods of time.
It's just a typical scenario, I don't know if it's possible in this particular situation. I guess we'll hear more about that when it's released and in later patches.
