They could, but then who would be your target audience? You wouldn't want to waste time making a whole new design when you can easily copy and paste the same thing, reducing your costs and only attracting people who didn't realize it's another throwaway shit-token.
Yeah you are completely right . They don't like to waste their valuable time and money for hiring designer where they can easily get new templates from marketplace. In some cases they prefer to use the old one just by changing fonts and colors. Actually they know that they will easily get some fools on their trap who don't care about team, whitepaper, roadmap and even the website similarities with old proven scam platforms. There is an interesting similarity between this kinda scammers and the immature investors which is both of them want to make some easy money.