If you had memorials for every driver who had died in F1 or motorsport in general, you'd need planning permission to change gravel traps. With all due respect, let's not go over the top.
Jim Clark was a legend - possibly the greatest driver of all time, bar none (including Senna - and yes, I'm fully aware that you can't directly compare generations, but he totally wiped the floor with some of the very best. Basically, if he finished, he won). With all due to respect to Ronnie Peterson, Gilles Villeneuve, Francois Cevert and the likes, they weren't legends - they had big fan clubs (I'm a big fan of Gilles) and each were on their way to becoming legendary, but they'd won very little.
Everyone who's aware that F1 cars once without wings will remember them in their own right, and that's enough. For those who had actually achieved legend status there should be a shrine of some description, and in Jim Clark's case, there are 3 that I know of.