I think your question boils down to: Do you have the budget to buy the horse you really want once it is showing? Or will you have to make concessions on rideability or talent or soundness to get your next horse?
In my situation, I cannot afford to spend $80,000 to get a really really nice green horse. So I spend $20,000 on a young one (yes, $20k ---- I wanted the talent I could only dream of, and talent costs money) and he is now worth approx 4x that.
I think that people often regret their decisions when they try to save money. Yes, those diamonds in the rough are out there, but ending up with a top horse for $5000 is a dream, not reality. I had to drop down and down and down until I was in a price range where I could pick and choose among the top horses I was looking at. For me, that was buying a 2 year old.
And, talking about the BEST in the age group, I have bought an in utero foal. Yes, it is a HUGE gamble, but he/she is by Baloubet du Rouet, and out of a Grand Prix mare by Cassini I. I could not afford these bloodlines once it was a living creature, so I bought the little black dot, and I am on pins and needles. Due date is in 1 week.