My general thought is that the cream will rise to the top regardless of lane condition.

That being said, if the question is.....does an easier shot BENEFIT a higher average bowler, I would say no b/c their edge has been reduced by allowing lower average bowlers to hit the pocket on a more consistent basis.  When everyone is able to get to the pocket easier (on an easier condition) the "carry contest" factor increases.  And while I will always take the more talented players, even in a carry contest, I believe that an easier shot doesn't benefit them for the reason previously stated. 

JMO

I don't agree with your premise of what happens to the higher vs. lower skilled bowlers on tougher Sport/PBA shots.
 
Everyone takes a hit, but my experience is that lower skilled bowlers take more of one. The 230 THS average bowlers will go down into the 190-205 range. They'll still make most of their convertible spares, but they'll leave more crap (washouts, big 4's, etc), and have fewer strings.  The sub-200 THS average bowlers will generally be completely lost. In general, the flatter oil takes their required outside bump away, and they don't know how to adjust. Their hook shot at spares that works on the THS completely disappears. It's not unusual to see averages drop down into the 140-150 range. Actually, it's not much difference than the shock you see at Nationals.
 
Again, I'm just describing what I'm seeing in my certified sport shot league. Maybe compromising toward some of the easier Kegel shots some of the less demanding USBC Red/White/Blue patterns would accomplish what you're suggesting.         

Easier conditions for the most part generally benefit the less consistent (ball speed and direction) competitor....they have more room for error that isn't previlent on the tougher conditions...also most easier conditions allow the black jack mentality...stand on 20 and hit 10...when you eliminate a path the lesser skilled competitor is unaware of where the play compared to the more skilled that understands ball their ball reaction and/or motion

I bowl better in a sport shot than I do on a typical house shot.

Depending on the contest I would tend to agree with the op.

Many mid average bowlers around here don't know how to play the THS. They stand a point A, try to hit point B, and play relatively straight. Lane condition does not effect them as much as the higher average bowler relying on some room to string strikes.

So the difference between their averages shrinks giving the lower average bowler a little better chance to beat the higher average.

In a scratch situation the higher advantage bowler probably stills has a large advantage. And the longer the format the bigger the advantage becomes. 

Going to an extreme. I know in no tap formats all the mid range bowlers are excited because they think of the single pin spares they miss. But in reality the high average bowler dominates because if they don't have to worry about carry and only about hitting the pocket they get 9 virtually every time.

I don't like carry contests. A bad break at the wrong times can doom you.

So many worry about the person they feel has an inferior game to them but appears to have the world to score. But in reality in many cases someone is feeling the same way about you as well.

ITZPS, also don't discount the amount of "touch" and speed control that naturally talented players have.....that plays a factor (in addition to accuracy).

Those things add up a lot over the long-term.

First off, I don't think it necessarily correct to call house shots easier in the sense they reward inconsistency.  All patterns reward players who can repeat shots over those who cannot, whether it is a flat tourney pattern or a walled up house shot. 

What house shots really reward is a more specialized release ( higher rev and more axis rotation ).  Tour players or those competing in sport leagues need versatility in their games to deal with patterns that can range in length from 30 to 50 feet. 

As a guy who prides himself in having versatility, I can still average high on house shot, but my carry is often not consistent enough to out average guys who I can beat on a 35 foot flatter pattern, or a 52 foot Badger. 

I guess that brings up a question I have asked many times.  If a guy can beat me by 10 pins a game on a 40 foot house shot, but I can beat him by 10 per game on a 35 foot tourney pattern, who is better.  The only real answer is who is better over a range of conditions.  I bowled a kid for our league championship who I know can beat me badly on  house shot.  In the championship we were bowling on the USBC pattern from last season.  He also thrashed me on that pattern after they opened up.  However, we recently bowled on the 35 foot LA pattern.  It played like a house shot off the corner for me, but this kid couldn't come within 20 pins per game of me on this shot. 

Bottom line the cream really does come to the top, but it takes a lot longer for that to happen than any of us often believe.  In that respect I don't think there is an answer to the original question of who benefits more from a house shot.