Altcoins were developed only so that people could mine on commodity hardware and it be impossible to mine on GPUs FPGAs ASICs... oh shit, why do they exist now?
Maybe it is time you take a strong look at Nxt! 
Not really, I was dissing them.
Regardless... there is an answer to your question...
Hence the drop of GPU support after 3.8. I agree alts are a side show, like clowns. IMHO they're only good for pump n dumps to make more btc
Bitcoins are to dollars as altcoins are to dimes.
When I have enough dimes.........
You can call them clowns all you want but I make my kids tuition payments with the altcoins I mine.
Bitcoins too, just for the record.
Just remember there are many altcoins that are 4000% more profitable than Bitcoins and at least TWICE as stable.
Everytime China farts BTC crashes.