UAD and WAVES, amongst several other companies, operate their business on the premise that there is some 'magic' as to why it sounds that way that is somewhere between difficult and impossible to manage (sufficient to enthuse a musician/producer).
As an owner of a UAD Octo and plenty of their plugins, but also lots of analogue hardware [1], including valve based compressors, EQs, and distortion units that are emulated by UAD. The plugins still aren’t there.
Especially for anything that needs harmonic distortion. I get the impression they use regular random number generators for some of the random variance, rather than trying to emulate the physicality of a valve. They just don’t quite have the mojo. For some things it doesn’t matter, but often music production is about a 1% improvement here, a 1% improvement there, which sums up to a lot. It’s still easier to get those wins with hardware. Like ‘mojo’ is the default setting.
A really good example is the Chandler Curve Bender [2]. I have the real hardware. A new one will cost you £6,700 - so it would be insane to buy one when UAD have a plugin version for £179. I have the plugin too. The plugin is my favourite digital EQ. It sounds great. But the hardware does things that the plugin just doesn't touch. The hardware is all discrete circuits (with massive transistors). I think the slight latency shift between the left and right channels gives a 3D-ness to the sound that the plugin doesn't even attempt. Anyway, this demo [3] really shows what it can do and why hardware is still in the game.
In many areas plugins are good enough, I tend to use the plugins for more precision and to have similar curves to the hardware, but there’s still a ways to go to until there’s parity with the hardware.
That doesn’t mean you need the hardware, plenty of successful artists use digital alone. Just it’s still easier to get ‘the good stuff’ with hardware.
I mean, audiophiles will gaslight themselves into believing and hearing what they want to hear. There are some areas where ok, maybe there is some difference to the sound, unlikely as it is, but once you start getting into "audio optimized SSDs" and "audio optimized ethernet switches" then it's all a 100% scam(and yet audiophile forums are full of people swearing that they can hear a difference in their audio tracks saved to an SSD that had a few extra capacitors added). So I'm not surprised that there are companies making money off that belief into what is effectively magic.
Audiophiles are ridiculous, frankly. I'm on the ATC group on Facebook. ATC make pro speakers used in many top studios, but they also make home 'audiophile' speakers. The speakers are amazing, but I often see them talking utter nonsense about how X sounds great or whatever, when they have pictures of their setup in an untreated room. Like they could even tell if the speakers are good in a room like that. They're hearing the room.
Audiophiles are like astrologers, it's all in the wind with them. But they shouldn't be confused with people into pro-audio for music or film production. The name of the game is to get the best sounding room you can, so that it's easier to make your art, there is a motivation to get it right and not be hoodwinked by the things you state.
Not that pro-studio people don't have their blind-spots too (especially around things like cabling), but they're not the same.