As an older person (52 y/o) who remembers a time when a lot more people I know (of all ages) were optimistic about the future, I believe the major factor leading to generalized anxiety currently is not about one event, but all the additive effects of massive and ever increasing wealth inequality piling up year over year.

That combined with little to no hope that either political party will do a damn thing to fix it (Democrats at least have some politicians who actually want to, but they are stymied by their own leadership, never mind the problem of not having any real national level political power currently).