You are humbled now. Often times you can't tell the difference. The normacy bias is, people that grow Cannabis commercially or NPO being caretakers use commercial seeds right? Wrong. They sometimes use their own, it's cost effective that way. That could very well be considered 'bagseed' as some of you define it. Most think that if it's a big operation or grow that they use the best of the best and they buy commercial, knowing the Cannabis will have the higher quality decision throughout it's production. I have a reason to believe people assume that all commercial seeds are good and all bagseed is bad or fair.
I think the definition of "bagseed" would be seeds found in a bag of cannabis sold at retail. Seeds generated by growers by deliberate pollenization of their plants aren't really bagseeds by that definition. On the other hand, seeds generated by accidental ("open") pollenization of commercial grows might well qualify as "bagseed". These seeds might well be excellent.
The point is, since most commercially grown cannabis is supposed to be seedless, almost by definition, any seeds found in a bag are the result of an accidental fertilization, explaining why they are always suspect in quality.
To respond in part to what you said above, most domestic cannabis is produced indoors under artificial lighting now.
For that kind of farming, typically commercial-scale growers start their crops using cuttings ("clones") rather than seeds. The reason is that cuttings display uniform sex and other characteristics, plus the turnaround time from cuttings is a good bit faster than from seeds. Since many of the most desirable commercial strains are hybrids rather than true-breeding strains, starting with cuttings is the only way to ensure crop consistency. In some cases, commercially grown strains might even be "clone only". . .these plants were hand-chosen possibly years before for exceptional characteristics from a number of other plants, and may not even have a corresponding genetically similar male to create seeds from.
The point is, domestic commercial growers generally do not try to generate seeds. They may do so under unusual circumstances, but again, if seeds are found in commercially grown stuff, the seeds should be assumed to be the result an accidental fertilization.
Assuming you don't know the provenance of your particular cannabis, since most cannabis is grown seedlessly indoors from pre-sexed cuttings, there is a pretty good likelihood that any bag with seeds in it was probably grown outdoors. In that case, while the cannabis itself will give you a good indication of the quality of the mother plant, the quality of the father plant may be utterly unknown.
Again, depending on where and how it was grown, there is some real chance that seeds found in a bag of high quality outdoor-grown cannabis were fertilized by a low-quality male, including even a low-potency wild male hemp plant. Seeds like that may well be a good bit inferior to the quality of the cannabis in the bag.
For the smuggled-in seeded Mexican commercial grade cannabis, my understanding is that those plants are grown in large fields outdoors, starting with seeds from a previous season, with the males not all culled. So with that seeded product, the seeds probably DO share the same genetics as the herb in the bag. If the bag contents are excellent, the seeds ought to be, as well.
