We've given up on keeping our initial arch docs/specs up to date.Should I worry?

At my current team, we started out with decent arch docs “how the system works” pages. Then we shipped for a few weeks, priorities changed, a couple of us made small exceptions and now we don't use them anymore and they are lost in time.

As the one who’s supposed to keep things running long term, I’m not sure if this is just normal and harmless, or if it's gonna hurt us later.

If you’ve been in this situation: should we just accept it? If not, when does it start causing real problems?