Yes, I know it's only the first week of bases and that this sample size isn't indicative of what will happen the rest of the summer but as of now there have been 74 games finished and just 18 of those 74 have been 1-run games. Which is roughly 25% of the games.
Looking at last years results
Astros: 44 games (27%)
Cubs: 42 games (26%)
Nationals: 48 games (30%)
Reds: 52 games (32%)
Arizona: 42 games (26%)
Pitt: 47 games (29%)
Two worst teams in baseball, the two best and two middle of the pack teams. Judging by these we can figure about 27-28% of games were 1-run games which aligns with what's happened so far this season. I'm of the mind that when RLs typically take a -150 favorite to +odds, it is more than worth the risk to take it. You're only losing out between a quarter and a third of the bets but if you're making bets daily the .60+ cents you save on every line you come out well ahead at the end of the season. Saw someone say RL's were sucker bets, I think they're a smart bet depending on the matchups.