Nothing I've said disagrees with what you just posted, and nothing you said negates anything I've posted, so I'm not really sure of the point...
"Anecdotal" suggests a small sampling, but that's inaccurate. The sample is actually quite large if you look at the entire list of HOF'ers and consensus great players who weren't drafted first round or weren't drafted at all; the sampling I posted of factual situations that actually happened are simply a matter of historical fact, and that list could be much longer if I cared to list all the all-time greats not drafted in the first round, plus great undrafted free agent players.
When we're talking about missing on names like Joe Montana, Johnny Unitas, Tom Brady, Ken Houston, etc. we're talking about players who have arguments as the best of all time at their positions, with a few actually being considered the best. Those are HUGE misses. Huge enough that it's strong proof that the process is not an exact science despite the way it's portrayed often in media.
It would be one thing to miss on some stray pro bowlers, but we're talking HOF players with whom the history of pro football could not be written properly without. That can't be ignored. Let's reel off a few more, there are so many... Andre Reed is about to go into the HOF, 4th round. Aeneas Williams is about to go into the hall, 3rd round. Fran Tarkenton HOFer, 3rd round. Mel Blount HOFer, 3rd round. Jack Lambert HOFer, 2nd round. Bart Starr HOFer,
17th round. Michael Strahan HOFer, 2nd round. Larry Allen HOFer, 2nd round. Night Train Lane HOFer,
undrafted. And some of these players like Bart Starr were playing at highly visible big time schools, so lack of scouting visibility can't be an excuse for why some were drafted so low. Teams knew about most of these players, and they just got it wrong. And that's still just a small partial list of all-time greats/HOFers not drafted in the first round.
If we were to extend this to perennial pro bowlers, all-pros, and players that are considered great but not in the hall and were undrafted, or drafted outside the first round, like, say, Jerry Kramer (4th round), the list would be pages more long.
As for the scouting model, obviously many things have been improved in the process over time as many things do as time passes, but the basic concept still holds true: Tallest, biggest, strongest, fastest, most durable, most skilled, most productive/consistent, hardest-working, best football IQ, order of importance changing depending on position. That hasn't changed much. The biggest change is that information moves a lot faster now and is easier to access because of all of the immediate media avenues available today, and because of that it's easier to scout in more places and there is a lot more data to review. But even "back in the day" before the more modern era we live in now, teams would find players at obscure colleges like Phil Simms playing at Morehead.
Whether they do a good job or a bad job, is highly debatable on both ends, but it's not a debate I'm interested in. All I care about is the end result. The scouts have missed on a lot of all-time greats and HOFers. And we're just talking about players who became great, that's not even mentioning the number of players who've busted and were major headaches like Ryan Leaf, or Kelly Stouffer, or were reached for even in later rounds and wound up costing a team in a number of ways like Maurice Clarett in Denver.