Heck going back to NuBus there was astounding graphics capability on Macs. When the company rolled out the G3/G4/G5 processors- they were stepping all over Intel based machines in big ways. And you could get aftermarket GPUs which were the equals of their PC counterparts.
The graphics lead of the NuBus era Macs began to wane when PCs adopted the PCI bus and 2D accelerators became the norm. By the time the G3 was introduced Macs were using the same graphics chips as PCs. When the G5 was introduced Macs were stuck with "Mac versions" of GPUs that were often a generation behind what was available on PCs.
In terms of CPUs the PowerPCs were only "stepping all over" x86 parts for very brief periods of time in each generation and only for some values of "stepping all over". The beginning of each chip generation say the PowerPC chips with an advantage over x86s but by the middle of the generation they were on par to slightly behind to really behind by the end of the generation.
What has happened since the glory days? Well- they stopped focusing on computing. It appears to be an afterthought. It's iPods... iPhones.... iWatches. The Mac is essentially a PC architecture with an alternative operating system. Anyone who knows that buys a PC, unless they think that Mac OS has something really compelling.
The Mac is a PC with an alternative architecture but it was in your "glory days" as well. The main difference between Macs in your mythical glory days and PCs of the same era were the CPU/firmware and the OS. PCs became far more Mac-like between 1984-1995 than Macs became PC-like. PCs stopped chasing IBM and started chasing Apple.
Putting aside for the moment whether iPhones etc are "computing", the Mac has not only remained a major player in computing but Apple is pretty much the only PC manufacturer with positive growth over the past few years. Institutional purchases remain Windows-PC but every college campus and developer conference I have seen is festooned with Macs.
What you're seemingly unhappy about and what most hardware geeks posting don't seem to get, is that "computing" on the PC today is dominated by notebooks. The typical PC (from any manufacturer) is a notebook rather than an aluminum sided tower. Your water cooled behemoth under your desk is a rarity.
The Occulus Rift or any other VR headset is no more going to support the vast majority of Windows PCs than it is going to support Macs. No laptops currently support the Rift and it will be years before a GTX980 equivalent ends up in even a modest number of notebooks. Only a very small fraction of desktops (themselves a minority of the total PC installed base) can possibly support the Rift et al.
If in fact VR is the "next killer app" on the desktop- Apple appears to have not prepared for it at all.
The fact that VR necessitates a desktop makes this claim seem a bit silly.