Thinking of privacy coins like Monero, do you think that they could ever rival or challenge Bitcoin in its position?
No because a coin can't become popular based on a privacy feature alone. And the most popular altcoin will simply copy the best anonymity design.
But in answer to the title of this thread, yes an altcoin could challenge Bitcoin:
I just thought maybe theres a darkhorse out their that hasnt been given enough hype for people to buy into, kind of like ethereum before it kicked off.
There is, but it hasn't launched yet. The name isn't even public yet.
Says every nonsense project about to post their ANN.

Nonsense?
https://bitcointalk.org/index.php?topic=1526067.0https://bitcointalk.org/index.php?topic=1518508.msg15283083#msg15283083https://bitcointalk.org/index.php?topic=1319681.msg15137236#msg15137236I just thought maybe theres a darkhorse out their that hasnt been given enough hype for people to buy into, kind of like ethereum before it kicked off.
There is, but it hasn't launched yet. The name isn't even public yet.
Then it's not a darkhorse.
Seems to meet the definition:
dark horse
noun
noun: dark horse; plural noun: dark horses; noun: darkhorse; plural noun: darkhorses
a candidate or competitor about whom little is known but who unexpectedly wins or succeeds.
"a dark-horse candidate"