The original concept for fantasy football was developed in the 1960s in Oakland, California. The GOPPPL (Greater Oakland Professional Pigskin Prognosticators League) was the first-ever fantasy football league. The players on the team looked nothing like they do now as it consisted of multiple quarterbacks, fullback, and even linemen! It was developed by Wilfred "Bill the Gill" Winkenbach, a part-owner of the Oakland Raiders at the time. Fantasy football did not explode right away; it slowly grew through the 60s and 70s but never quite gained the popularity it has today.
Fantasy football didn't become widely popular until the late 1990s when the first online fantasy football program was launched by CBS. Since then, the growth in the pastime has been immeasurable. Much of the growth can be attributed to the popularity of sports betting. After the possibility of online fantasy football came to fruition, the game exploded. It became so popular fantasy football was advertised, and fantasy football analysis shows were created reaching an even wider audience.
Controversy gets attention, plain and simple. With websites like FanDuel and DraftKings promoting daily fantasy sports, the question of whether fantasy football betting was gambling had to be answered. Many states have banned the websites from operating within their borders, but the websites still function well, especially with the help of Vegas betting.
Overall, based on its growing and continued popularity, you can expect fantasy football to be around for a long time.