Me too I prefer the real thing, and certainly not all hardware can be replaced by software, and not all software is cheaper but in the price range of the Xenyx, I´d say it´s not a problem to replace hardware with software.
You just need to know if you´re monitoring through Cubase during recording, you might have to deal with latency. Which you don´t with the Xenyx. But also the ineterface should provide a zero latency monitoring possibility - then without the Cubase EQs though.
Apart from that, there should also be mixers that allow for more than two channels recording, like the Presonus StudioLive series (Firewire), The Behringer X32, the Yamaha N8 / N12 (Firewire), Yamaha CL series (Dante), for example.