Thats an interesting idea but it would look very greedy and unproffesional to do this as the owners make a lot of money from this game and can afford it but instead the customers will pay, which would be wrong. This will completely ruin a brands image and reputation hence why, nobody tests this out. You cant ask your customers to pay for your wants, they are only here to buy your products/services, not finance your business plans just so that you can save yourself money.
In my opinion we shouldnt think about advertising this game as it cant grow because currently it doesnt have the resources to grow. The servers need to be expanded+upgraded, a new tutorial would have to be made that gives a more fulfilling description of the game, the map would have to be expanded, etc. Once all of this is done, you will see an increase in playerbase if you use effective advertising methods such as youtube/google ads as millions of people can be targeted and are classified as potential customers. This would cost so much money but its the best thing i could think of.
Note- I am not arguing with you, I am just giving you constructive criticism because both of your ideas cant be used in the business industry. There are more backlashes and negatives than positives.