Is the saying, "The internet's written in ink, not pencil" accurate?

With things shifting around the internet the past year, and also just...Having been on the internet for awhile now, I feel like this saying, while decent as a cautionary measure...May not really hold up past that. Am I being a little naive though?

Is some decade(s) old post of mine from some old forum really still floating around somewhere out there on some random old server chugging along?

I feel like even in the corporate web, a bunch of that old data's probably been long lost courtesy of costcutting measures and businesses going under.