Venture never lived up to May's expectations and the operation had pretty limited geographic scope (Chicago & St L, don't know about anywhere else). They also started out after other chains had opened discount stores. Caldor did not do so well under ADG which I think had spunoff LS Ayres' Ayr-Way stores to Target around the time of the Caldor acquisition. ADG did things like convert underperforming mainline department stores such as Stewarts in Baltimore and some Lord & Taylors into Caldors with varying success. The Venture stores were somewhat similar to Caldor but larger and with more hardlines and less of well-defined niche. Caldor had had a a very devoted following in New England which probably didn't translate elsewhere, esp. with people other than the couple who founded the chain being in charge. After the May-ADG merger, May probably took a hard look at operations to see where they could raise cash or cut losses and the discount stores were a logical spinoff. They probably saw that Target would eventually dominate their segment without a massive expansion that could ill afford. I shopped Caldor on their hometurf when they probably were at their peak. I wasn't close enough to their DC/Baltimore stores in the 90s to see if their merchandising had held up or gone down hill.
Bradlees' fortunes probably were tied to those of parent Stop & Shop. They entered and then quickly exited markets without Stop & Shops in the Southeast and they probably were adversely affected by Stop & Shop's unsuccessful entry into the NJ suburbs of NYC. Bradlees were a little nicer than the average KMart but not some place you'd go out of your way to shop. They really didn't have a particular merchandise niche to justify a special visit, so only occasionally went there--Caldor and KMart were closer and Stop & Shop was not my first choice for groceries.