Re: This is actually largely irrelevant
Except.... that if you pay for large scale enterprise support it costs nigh on as much as an MSSQL licence for the same feature set. Just like if you pay for Red Hat Enterprise it costs about as much as Windows Server.
And if you don't buy support you need staff who can support it, which also costs money. If you operate at IBM/Google/Facebook scale it's a saving to support it yourself, but otherwise even for large blue-chips it doesn't make sense.
Products are priced the way they are because that's the most they can charge without making their customers switch. Ergo, at any price point, everything is usually approximately equal value for money..