It's expensive on purpose, it's a design choice to ensure that there are always pixel sinks. If it wasn't extremely hard to get the pixels you want then within a few months the world would be saturated and demand would be tiny. As it is people will always be trying to reroll to get that one thing they want, in the color they want.
Gives players a market to sell pixels, gives devs a way to earn cash, and helps servers by providing CPU sinks so players have reasons to optimize their code and ways to spend their bucket without additional server strain. Downside is that it sucks as an experience to use, but over time it'll suck less as the world becomes more saturated and demand falls. I hate lootboxes but in this case given there isn't another way to take pixels off the market it makes sense to gouge on creation.