I'm not talking about making an Unreal Engine competitor, but a passable 3D engine that looks good and is acceptable. Do you think it has become easier or more complex?
Not necessarily, unless you're trying to incorporate as much tech as possible into one engine like UE5 or something. Also, I think people underestimate how much game engines are modified to suit specific purposes. Sometimes porting an Unreal or Unity project can require hundreds of thousands of lines of bespoke code to get it working on a certain platform or to fully integrate a specific technology.
> or more easy due to the vastly increasing hardware power we have available?
This, definitely not. Rendering tech got more complicated, in a good way, but not in a beginner-friendly one. For example; ray tracing is a bit of a "holy grail" for physically-based rendering. It's been attainable on consumer GPUs for a while now, but reaching a realtime framerate requires an incredible amount of software trickery.
I now think my initial love of Vulkan was in no small part easy to evoke because of 20 years of deep graphics and physics engine programming. I knew where the designers of Vulkan were coming from. So it was kind of easy to see what they were trying to do. If you don't have that experience with the past, and you just sit down to use modern APIs today, good luck. Even webgpu can be a little off putting if I'm honest.
So I'm thinking that maybe there's just so much more to graphics programming today, that beginners really have to be supremely motivated to wade through all that to get some kind of understanding. And I'm not talking about becoming elite, I'm talking about just being productive at all.