Eight teams currently sit at least ten games behind the leader in their division. Half of those eight reside in the AL East. Yes, the Red Sox are dominating.
The Yankees, however, are the only team of those eight with an Expected W-L record of better than .500. So they've got that going for them, which is nice.
Currently 4 games below .500, their Expected Win-Loss record (a complicated formula based on their runs scored and runs allowed) puts them at 6 games above .500. The next closest team sitting 10+ games out is Toronto, with an Ex W-L of 1 game under .500.
The Red Sox, meanwhile, sit 2 games better than any other team in all of MLB and 2.5 better than any other AL team. Their run differential of +75 is better than any other team, indicating they have not been a fluke. They're only 1 game better than their Ex W-L.
The unluckiest teams in the majors are the Yankees and the Cubbies, both at 5 games worse than their Ex W-L record. St Louis, Colorado, and the ChiSox have been the luckiest, at 3 games better than their W-L record.