The state of the credits slightly bothers me too. I'd also say the reason was to "save money" but considering the MSRP it seems a bit of a money grab if that's the case as the credits are pretty bare-boned and shouldn't take much to "restore". A few episodes I've seen *do* have restored credits but I've not payed enough attention to see if those were more "generic" in nature (no guest star or cast change). If they could see fit to do a few then why not all? I seriously doubt it was because of sponsor logos because those would not be on the 35mm master or negative but only on prints sent to the network for airing.
I'm 2 seasons into the set and, other than some continuity issues (which can be attributed to poor production/management/scripting and/or lack of a production bible), that's been my only real gripe.
If the state of the credits is any indication of what they were given to work with for restoration I'm amazed there's not more damage evident in the episodes themselves.
The end credits appear to have come off some badly transferred 16mm syndication prints while the audio clearly is off the same masters as the episode content.
Sponsor logos would have been on any 35mm negs or prints. These transfers certainly weren't from the camera negatives. I'm just pleased that the episodes look so good. The credits are a distraction but I can live with it.
What's more annoying us the terrible job they did with the bonus episodes of the Bob Cummings and Stu Erwin shows which look almost as bad as those end credits.