Nowadays peripheral ICs are usually accessed over SPI, I2C, onboard USB, or some other indirect method. It is common for complex devices to have a micro on the other side handling I/O requests rather than spilling their guts to the world. That "other micro" could also be a full blown multi-core processor with an MMU running at hundreds of MHz and beyond. The difference back then is that parallel bus interfaces were king and custom ASICs couldn't necessarily afford the gate overhead of an embedded micro at all.