I don't own ANY hardware, and don't plan to invest in any.
But someone previously stated that the physical inputs, converters, etc. on a hardware module at $10,000 are going to be far better than using, maybe a $300 interface with converters NOT necessarily designed for it, which I'd guess cold ultimately give a plugin a different sound than its hardware counterpart.
I'd also guess that having things like compressors and EQ's in the chain pre-conversion could make a big difference in the sound, something that doesn't even seem to be an approaching
possibility with plugins.
But really, they're all just different tools for different jobs and different end-products. YES, you won't get the same sounds. YES, you're allowed to use whatever combination you like....
I only do the studio stuff for fun, arranging is more of my cup of tea.... so I'm sticking with plugins!