There's people who start off with near nothing and end up with millions of TC without having to muster up any USD to begin with. There are a small minority yes but it's not impossible. Two examples would be rags to riches participants and everyday duelers in lobbies. Both involve the notion of investing enough time to acquire some sort of skill inclining you towards the goal of obtaining more TC. 99% however would be no where near accurate.

The idea that (albeit not ridiculously high tier but sure,) mid tier items should be just as easily accessible isn't realistic or practical for that matter. The value and demand of an item is not only dictated by the appeal but its worth in in-game currency. Say if a mid-tier desirable color such as Azurite was obtainable via a week of game-play, I highly doubt a player would feel the sense of achievement they sought out for (or didn't). Instead, they'd look up at other stuff you could only realistically get with real money and desire those items much strongly. In the end, its just frustration observed in every game (that involves purchases with real currencies) of "that item is so sick, why does it cost so much?"

Where the item is probably sick because it costs so much and the only easy way to get it is spending real money.

An alternative would be a couple of freshly launched beginner tier colors I would presume.