in 100 years people are not going to be moving whole bitcoins (thats the point your not getting)

much like we are not in the era of 2012 where even i was normally moving 1000 bitcoin at a time, now i only move 1btc at a time and in the future will only be moving xxxsat amounts at a time

much like ancient egyptians moved tonnes/kg of gold at a time and now we move ounce, grams

you are again thinking that in 100 years the blockchain will be producing more then 1btc reward per block to be producing $5 trillion per block. which you now admit is not feasible in comparison to a countries GDP if you multiplied that across a demograph of holders..

what you need to realise is in dates like 2012 a "whale" was someone with 10k coins+ now a "whale" is someone with 100coins+ because the fiat value moved up, and in the future whales will be the ones with 1btc, then 0.001btc
just looking at the whale position shift of 15 years will show you the shift pattern of the next 100 years
individuals wont have whole bitcoins in the next century.. get it yet (individuals dont have whole tonne gold bars)

...
as for your horse analogy.. a average horse lifespan is 30 years. you are trying to say that a young 3 year old horse is a dying horse because its life is more than 25 years, so you want to shoot a healthy 3year old horse now because you fear its lifespan of over 25 years is not enough

to you a 10year old human child is a dying human because its lifespan is 80+... so you might aswell kill a 10yo kid now out of fear of it getting old in 80 years
..

i understand you are a ethereum fanboy and have no concept of bitcoins features, functions and economics(as proven in other topics) but it seems you have gone completely blind about real basics that can be found out in just 10 minutes of research.. or just sitting in a chair with a cup of coffee and actually just thinking rationally about real life stuff and the numbers