I think there was a thread like this a while ago and Lyn brought up a good point that really stuck with me. The miniatures that were considered 'top' 25yrs ago are not what is considered 'top' today. If you want to see what i consider modern miniatures that are 'top of the line' today take a look at a few of these.
ERL Volontair
Buckaroo (prob will never go out of style)
Little King's
Michigan
Buckeye WCF
Alvadars Double Destiny (heavely buckaroo bred)
Most ERL minis
Champion Farms Nighthawk
Glen Oak minis (most of theres are very nice and modern)
Those are just naming a few of what i think is 'top' and winning today. Sorry to give you mostly farm names
Another thing i noticed, most of the 'top' miniatures today are heavely Shetland bred or are AMHR/ASPC double registered. Buckaroo has so much shetland blood in him i wouldnt know where to start. Of course i think Rhotens Little Dandy and all the big ones are here to stay. LTD is a faverit of mine along with Little Kings White Russion, Buck the System, Dippers Duffy and ERL Volontair.
IMO, ERL Volontair and Double Destiny are just two of the bloodlines that i am really interested in. They are very modern IMO.
Hope i answered your question, i cant answer how they got there ..they just did lol. They have something that really stuck out, buckaroo is 29 (?) years old and today is still considered modern. Now go back 29 yrs ago when the minis were not as refined/dishy ...buckaroo was a horse way ahead of his time!
(I'm trying to ignore all the comments above and just answer your orignal question)