The Price of Rhino Reel to Reel tapes $299.00

I have three RTR decks in my collection: Teac, Pioneer RT707 and a 60’s all-tube Sony.

Extremely low volume production here - a niche within a niche (within a niche). Extremely complex equipment that either has to be tediously restored from vintage, or designed & built all-new at great expense. Not really surprising to have this pricing when the intended target market doesn’t bat an eye at 100K a pair of speakers, 100K amp, etc. Of course they’ll also go the extra mile for external head amps, etc

$300 a tape (or more) is not something I’ll partake in. And the media selection sucks. You can still enjoy the warmth of tape on a more reasonable budget with vintage decks (I have a Pioneer 909, and had a 1020L - both fantastic sounding) and vintage tapes, including needledrops! I have ~200 needledrops on great Maxell tape that are wonderful. People go on an on about the "warmth" of vinyl, but really tape is where the most vintage warmth can be found. 

I've also heard the state-of-the-art modern tape playback w/ expensive tapes and it's truly top class, but the expense and limited library make it a no-go here. 

Does not surprise me.  A good quality RtR recording offers unique charms and things like that will always garner a premium price to some  extent. 

Are they dubs from original masters?

Analogue Productions started offering some of their albums on reel-to-reel a few years ago, as have (I believe) Gillian Welch & David Rawlings, and at even higher prices than Rhino.