What gives a route the “R” rating

Mr Rogers wrote:

R has no relation to the crux. It could be R at the crux or anywhere else.
...

In line with what many people have said:
PG13 is scary but not really dangerous. Staying "heads up" is recommended and a fall might have a slightly higher chance of hurting ya.
R is you really should avoid falling as doing so is gonna likely mess you up real proper, but is probably not gonna kill ya.
X is you fall, that's likely the last fall you'll ever take. An X section of a route, or an X route, the rope is really is only good for body recovery if ya blow it.

All of the above is not how I and most climbers (nor guidebooks) define "R" or "X."

A route with an "R" rating will be poorly protected at the more difficult sections of the route. 

E.g., a 5.10 route, that may be run out on 5.6 or 5.7 does not necessarily warrant an "R" rating.

The fact that a fall "somewhere" on a climb could be bad news isn't the criteria, at all. The idea is to give you a heads up that "you better be very solid at the grade" as the protection is poor, very sparse or perhaps, with "X," basically psychological.

Randy wrote:

All of the above is not how I and most climbers (nor guidebooks) define "R" or "X."

A route with an "R" rating will be poorly protected at the more difficult sections of the route. 

E.g., a 5.10 route, that may be run out on 5.6 or 5.7 does not necessarily warrant an "R" rating.

The fact that a fall "somewhere" on a climb could be bad news isn't the criteria, at all. The idea is to give you a heads up that "you better be very solid at the grade" as the protection is poor, very sparse or perhaps, with "X," basically psychological.

I think this thread has enough responses that are in alignment with my understanding to maybe back up my mediocre synopsis as generally the common understanding of the term R when applied to route rating.
Plenty of guide books align with this opinion too, despite some books having different meaning to what R is. See edit.

It is a great reminder to read the guidebook notes to see if they maybe have a different meaning of terms commonly used.

But who knows, maybe this thread sample size is just too small and my stance is actually outside the bellcurve.
Nah. Looking through a handful of threads on this topic I redact the above concession.

Edit:
History if seriousness ratings - James Erickson developed a safety grade based on movie ratings in 1980 and they went like this-
G: Good. Protection is more than adequate, with placements available to minimize the fall factor. A leader who places gear properly should never be in danger of hitting ledges or the ground in the event of a fall.

PG: Pretty good. Protection is considered adequate, although moments where there is ledge-fall potential may exist.

PG-13: Moderate. Protection is generally good with perhaps a section where there is potential for a long, risky fall.

R: Runnout. Even with perfect gear placements there are long sections of unprotected rock where if a lead climber fell they would be subject to a long, dangerous fall likely resulting in serious injuries.

X: Extremely runnout. If a leader falls on an X-rated climb, death is a real possibility.


Now since were using guidebooks as the standard.....
I present 5 authors interpretations.

Carville

Jackson

Lewis

Dneba

Freedom of the hills

all of the examples are from far more respectable opinions than my own that are not in alignment with your position... including the real kicker, the "inventor" themselves, James Erickson.

Life is like a box of chocolates, and some folks have a hard time with that.