Quite apart from the increased complexity, the most important difference is that there's a minimum speed as well as a maximum speed for modern DDR RAM, which means there's usually quite a narrow window of achievable clock rates when getting an FPGA to talk to DDR3.

I suspect that's why the author chose to use the DDR for video: It's usually easy to keep plain old SDRAM in lockstep with a soft-CPU, since you can run it at anything between 133MHz (sometimes even more) and walking pace, so there's no need to deal with messy-and-latency-inducing clock domain crossing.

Streaming video data in bursts into a dual-clock FIFO and consuming it on the pixel clock is a much more natural fit.

But, a plain answer: Via Eden boards. still use north/southbridge architecture, and are from the mid 2000's.

It's just modern Windows/Linux that have discontinued the ability. Or, perhaps you have 16/32 and 32/64 and are unable to do 16bit on 64bit machines- which still boils down to "operating system."

By far the biggest issue though is that even the Via Eden processor is significantly faster than a 486- and lots of software (especially games) from that era used no-op instruction loops for timing and timers. This results in games like The Incredible Machine's level timer running out in half a second or less.

https://archive.is/UD0vH