But my point was that you can run OpenWrt on very small devices[1], but not pfSense. It is true, of course, that today's bandwidth requires more powerful devices.
[1] A friend of mine works in embedded systems, and to him 16 MiB of RAM would be ginormous.
That was the case back then, but newer routers have to be a lot beefier just to handle the throughput of faster net connections.
I've got a WRT1900ACS running OpenWRT/LEDE at home. 1.6GHz dual core and 512MB of RAM, and it's not really even top of the line by today's standards.