ef: I won't really disagree with you, but notice my disclaimer... I am keeping my opinion based on my own limited personal experience. I am mostly focusing on one certain A.P. Indy son and one certain Storm Cat son. Colts sired by these two are not "retired early to stud" and do race for a few years, so the tendencies can be noted.
The Storm Cat son's offspring do very well early on but seem, to me at least, to get "washed up" with age.
The A.P. Indy son's offspring don't do well early but do get better.
Around here, they're running against the same horses as 5YOs that they did as 2YOs. So, yes, they ARE getting better... or maybe all the other horses just get worse.

But, since I know a lot of these horses personally, I can vouch for the change in their physique, attitude, competitiveness and determination as they age. Many of these horses just don't put their heart, soul, and mind into their races until they mature. Once they get a little maturity, their competitiveness surfaces, they want to win, they turn in faster times, etc... not in all cases mind you, but in enough to make me believe that the trend is there. Not to mention the fact that I've seen these horses continue to grow and mature physically as they age... as 2YOs and 3YOs they are only a fraction, mentally and physically, of what they will become.
Freddymo: You know, since we all know that will never happen, I hadn't given it any thought. Oh, you're probably right... I would love for some of his offspring to have the chances that some of the higher-dollar horses have. However, since I haven't paid the slightest bit of attention to the mares that the Phipps own, I can't really say whether I would be excited about the actual matches or just the fact that they were the Phipps' mares!

I mean, isn't it possible that their stock just doesn't match well with the Indy line? Or maybe they aren't raised or trained in a way that benefits them as individuals?
Before someone jumps on that... I am in no way trying to indicate that these horses aren't cared for... but come on, not every horse thrives in the same environment. We have mares that match well, IMO, with the Indy line. A couple (1 in particular) will also do well with the Storm Cat line, but that's not what we're focusing on, so that's just not what we have. Here's more what I was getting at... and this is just a rambling thought that I've had in the past but never voiced because I'm fully aware of how silly it sounds
We have had, by far, more Indy line foals to deal with over the years than foals of other bloodlines. We've had only one Indy line foal get hurt, and that was
SO not his fault (and he completely recovered!) Other injuries have occured to other lines that we've had... one to a Miswaki line foal (of which we've only had two, and it took over 1 full year of training to get the other one over her "issues" and finally to the races!), 2 out of 2 other Mr. P line foals (exact same type of injury, fully recoverable, just a pain in the butt to deal with), 1 out of 1 Buckpasser line foal (again, fully recoverable). Now, out of I don't even know how many Indy line foals... nada.
Here are some
personal (as in my own... I'm not saying this is true across the board) observations: our Indy foals
hate to be stalled. Our Indy foals run and play
HARD (really, really hard) with the other horses. Our Indy foals have very calculating minds and THINK about things... they're smart.
Maybe, just maybe, keeping Indy line foals in protected stalled environments (aka headed for the sales, etc.) just doesn't do them justice... just as some people are perfectly happy and mentally content at a desk job and others simply can't handle that. I know this is a real jump, off the wall, totally insane, whatever... but these are just thoughts that I've had while observing the offspring of different horses throughout the years...
OK, waiting for all the "you idiot" comments to come rolling in...
(Hey, you know what they say about opinions....)