It is but that Not really the full story as most are for off field issues mainly financial like york moving issues and Darlington were basically shafted.Of the bottom 7 sides I've seen 6 play in the league, three of them against the Boro. So easy to drop through the divisions.
Grimsby Town have given us some thumpings, even during my timeHereford was a league cup game if they are included. Same for Scarborough.
Chester and Darlo and York are very rare league opponents for the Boro.
The biggest drop in recent years is probably Grimsby Town (National League Premier). They were a top half Championship team at one stage in modern times and the area has a population of around 160,000 big enough to support crowds of 8,000 plus. They have reached the semi finals of the FAC twice.