It's not becoming more popular. Everyone and their mom knows what pokemon is everyone under the age of 30 knows what pokemon cards are. It literally CAN'T become more popular. In reality you have more people scalping product which is constricting the supply, but demand for the product remains the same. If people choose to buy from someone scalping that's their own business but the supply is overwhelming and continuously being printed so prices will reflect that and stagnate then dip. It's the same reason champions path is going for the same price it was last September and hasn't increased despite it becoming "more popular". It's printed cardboard they can make more of it.