Very thoughtful, very good post.
Now let me offer the flipside to it
I can agree with you if you have a (meaning single) very good stud. And that's all you've got. Then, yes, you might want to freeze him if you haven't been able to build a bloodline off him yet. You need to get your bitches in order, that nick with him well, and you need to ensure that these breedings actually do happen so you can realize your breeding goals.
However, if you've already got several breedings done with this stud, then there is no reason to freeze his sperm if his offspring really do carry/reproduce his good traits. Why? Because if this stud dog IS reproducing his traits in his offspring, why then you already have his traits in those offspring, don't you? And if this stud is NOT reproducing his traits in the offspring you have, then what the hell do you need to keep breeding to him for?
Let's take the Jeep example. I would absolutely breed to several of Jeep's sons over the original Jeep (but, no, Tab would not be one of them). If you know what you're doing, and stay up on the line, you can follow the quality very easily in the lineage. For example, I would happily breed to Jeep's son Long's Werdo ROM over the original Jeep, all-day, every day. If Werdo died, I would gladly breed to his son Bodysnatcher's Ch Rutkus ROM. If Rutkus died, I would happily breed to his son Ch Slim Shady ROM, etc. In other words, I have zero need for Jeep semen if I am into Jeep dogs. I can get these (or better) qualities by being informed and following the right Jeep descendents in my commitment to the line.
In my own line, while I may have been bummed that Poncho stopped producing at an early age, I quickly learned I did not need to keep breeding to Poncho "himself" to repeatedly and consistently get the traits he threw that I valued. Poncho's sons and daughters had them and threw them! If they didn't, then why would I need to keep breeding Poncho dogs, if his traits were so easily lost? The fact is, I continued to breed my line (and very successfully) only because Poncho was so prepotent in his ability to throw the key traits that he had into his offspring.
Sure, if I had a lot of money, and Poncho would have stayed fertile, maybe it would have been nice to save a gazillion vials of Poncho's semen. Yet, the only reason for me to continually breed to Poncho "only" would be for my ego ... to build the number of wins/Champions off of him alone to make his stats increase. While I admit it would have been nice to have Poncho's semen till he was 12, and to breed him to ten-dozen bitches with his stored semen, this would only be "nice" because Poncho would tower over most stud dogs in his production record. Yet the truth is, percentage-wise, he already does--he just did not saturate the market with his direct offspring for 2 decades. Yet, when Poncho dogs faced dogs out of some of these other famous studs, who did saturate the market, Poncho's offspring whipped their ass 8.5x out of 10, and that is all they needed to do.
This brings us to my point: from just a few breedings, Poncho had plenty of sons that were as good as he was (and/or who threw dogs every bit as good as he could throw). So I was able to establish a line off of him with what I did have. So, yes, once you've established your line, and locked-in your traits, you really can get 85-90% game, good dogs. Maybe not Ch, Gr Ch, but game and good YES. Poncho's son Duke Nukem had incredible percentages as a stud. Not all dogs off of him won, but most did, and the sons of Duke that lost did so game or DG in 2-3 hours. In particular, Duke's son U-Nhan-Rha was a very badass dog, who (although not matched) had a heavy mouth and no weaknesses. As a stud dog, no dog matched off of Uey ever lost, but 1, and that was his Championship bid, which he lost game. That dog's brother did become Champion, Northern Express' Ch Red Bull. So, you bet, I would breed to any of these (and other) key linebred Poncho dogs every bit as confidently as I would to Poncho himself.
Therefore, IMO (and I have lived this, and know this to be a fact), you do NOT need to keep any "one" dog's semen around to keep the quality alive in your dogs. The only reason to keep dog semen around off of any one dog would be if that dog is truly great, and you have NOT YET established a line off of it and are seeking to do so (but don't yet have the right bitches to do it).
However, if you have gotten 6 (or more) breedings off of that stud, and have made a couple of key inbreedings back to some daughters, you absolutely do not need any more of that dog's semen ever again. Because, if that stud really is a good producer, and you know what you're doing as a breeder, you should have all of his good traits harnessed for as long as you want to breed them. But (again) if that stud is really not good, which means he failed to pass on his traits to his offspring after half-a-dozen breedings or more, then why the hell do you need his semen?
Jack