I've never needed paid professional linux support. Or windows support. Or mac support. Or android support or any of that.
I think the issue is...once you develop enough in-house Linux knowledge you don't really derive a benefit from paying for support.
Tbh, the only kind of "linux support" I'd really want is overnight sysadmin support so I don't get calls at 3am. I suspect that isn't the kind of support you have in mind.