Why was Roblox tix removed?

The impetus behind removing tickets is not to make more money. The primary reasons have always been product simplicity, botting, and not incentivizing certain behaviors.

Is Tix Coming back to Roblox 2021?

However, it is quite less likely that Tix will be coming back. The same Twitter account has stated earlier that Roblox might try to implement another non-premium currency but it will have more restrictions than Tix.