I've struggled with this one. I can see why owners flock to the most successful trainers. I totally understand that. Owners are making significant investments in the business and want their best shot at a good return.
But I do worry that this trend will tend to make the game less competitive. Fewer horses being bred, many being trained by the same big names feels like a recipe to shorter less competitive fields.

They have huge barns but mostly focus on the cream. — Gregory Byrnes

I recall someone who worked in [name redacted] barn talking like that about him when it came to 2-year olds. The actual quote was that [name redacted] had a "churn 'em & burn 'em" approach.

He went on to explain in more detail: Let's get the horse on the track and see if he/she is precocious. If the horse gets hurt - oh, well. Wasn't going to amount to anything we can use anyway.