Will there be an opportunity cost if the money is invested in individual stocks or an S&P 500 ETF rather than starting with WDIV?

Hi all, newbie here. I'm trying to understand the economics : If I were to start with WDIV with $1k/m today to get $1k/m back in dividend, the portfolio should be around $400k and up, which in this case would take around 2 decades. Is it correct that there would be an opportunity cost if the same money is invested in some individual stocks or, say, an S&P ETF?