There's nostalgia meaning a belief in some sort of golden period in the past, when everything was better than nowadays - people were kinder, more reliable, more efficient, more honest etc etc. You would actively like to go back to that period and leave all the deficiencies of the present day behind.
Then there's nostalgia meaning the belief that standards used to be higher, people took more of a pride in what they did, whereas now the bare minimum will do and sloppiness and mediocrity are rampant. Journalism has degenerated into tittle-tattle, bad grammar goes uncorrected, letters from businesses make no sense, and so on.
Well, I've never believed in a golden period. Whatever years you look at, there are plenty of failings along with the benefits. In the 1960s for example, often seen as a glorious decade, yes, you had high salaries, cheap housing and free university tuition, but you also had homophobia, much more racism, and until 1967 abortion was illegal.
But the problems of previous eras tend to be conveniently forgotten while the problems of the present are all too evident and emphasised day after day by the media, often blown up out of all proportion.
As for slipping standards, well, they are and they aren't. Yes, standards of some things like letter-writing, journalism and degree courses may have declined, but what about the coronavirus vaccines, or complex medical treatment, or computer software, or the increasing reliability of cars? No diminishing standards there.
Personally I've no desire to turn the clock back. I think I'll stay right here with the internet and all its little miracles. So thanks but no thanks.