Not the other commenter, but they likely meant stability with respect to device drivers. The kernel is great at not degrading with a high uptime, but there’s consumer stuff that’s just perpetually unimplemented, buggy, or minimally-functional:

• Sensor monitoring on Ryzen platforms
• Realtek NIC chipsets
• Nvidia cards and proprietary drivers for anything and everything other than compute workloads
• Nvidia cards older than the RTX 2000 series and FOSS drivers
• Peripherals targeted towards “gamers”

None of this is the kernel maintainers fault, of course. The underlying issue is the usual one of shitty corporations refusing to publish documentation and/or strategically abusing the legal system to stifle reverse engineering for interoperability.

Hellwig was a bit crusty about being overruled by Torvalds, it seems.