It is in a way a good thing that a mature library like jQuery isn't released too frequently because all the websites that use it works just a little bit snappier because jQuery is usually already available in cache in the browser from some other source and if not, then the nearest CDN probably has it.
Releases matter, as that is what gets the changes to end-users, and infrequent releases typically indicate a stagnant project.
I am not trying to disparage jQuery, rather the opposite, since it is mature and reliable software. Open-source projects, like houseplants, need stewardship, and jQuery (along with other JS Foundation projects) may be overshadowed by JavaScript ecosystem hype-cycles that are competing for mind-share.
As stated above, open-source projects need stewardship. Otherwise they languish. I genuinely hope for jQuery to continue as a project and community endeavor.
Would love to know more about that because looking at your website it's just plain HTML with JQuery.
Which ,in my opinion , is how you should be building landing pages.