Souls + Gems + Traitstones (mostly major) + maybe even a yet to be determined daily resource. The others can be earned, the gems so you couldn’t hoard them (more mythics would not be entering the economy, just more of the ones you want), and the daily resource so it can’t be exploited or just bought into.
It actually doesn’t equal out to the same ratio over time. Every troop that is released is in some way much cheaper when it is initially available than trying to get it later on. In the case of mythics, they have a one week exclusive period. Failing to get it during this exclusive period means you have to randomly get it to drop from an ever-increasing pool of mythics on top of their already ludicrious base rarity. In the case of kingdom mythics, you can “target” them again when their kingdom event rolls around, at an average of (assuming you were using VIP chests before) three times the cost, with the added burn that you wont get anything else useful from that cost and failing to get the mythic will be all the more devastating. For non-kingdom mythics, your chances keep going down every month. You will spend much less to get the mythics, overall, if you can get them on the week they are released. Even if you started with none and attempt to pull them all randomly, chances are you are going to double up at least a few times before you are finished - and that is if you are lucky.
Right now, maxing out every guild task and collecting income nearly every time it is available every tribute leaves you just ahead of the curve for getting them on average, but unless you have a ton of resources saved up from before the guild patch, a bad streak can easily wipe you out. This leaves you with a missing piece of your collection where absolutely no reasonable gameplay or purchase method can move you toward. You basically just have to accept that you don’t have it purely because you weren’t lucky.
Again, this is not the same as not earning it because you didn’t put forth the effort - it is the fact that currently, your effort, dedication, and even monetary investment are all secondary to the RNG. It’s okay to have “chase” drops, but how exactly is one supposed to “chase” something that they have almost no influence over getting and keeps moving further away over time?
So, in all honesty, they probably wont go for being able to choose a guaranteed mythic no matter what the cost. How about this, though? Once you obtain a base mythic, you should be able to “lock” it to prevent any more copies of it from dropping. Most people are still going to be accruing mythics slower than they are released, but I have to say, pulling a duplicate mythic you don’t need after spending a ton of resources trying for a random one you are missing feels worse than not getting one at all. Anyone that doesn’t have a mythic now without a ton of banked resources would still be getting at most 3 every 2 months, if in a top guild, or at least a guild that finishes all the base tasks, and over a year for a complete collection.
As it stands now, the time metric for a complete collection of mythics, unless you have them all up to this point already, is “never”. Maybe that is the intent, but if it is, you have a collection game where it is impossible for most players (especially those entering the game after the guild patch) to complete the collection.
