[TrianguloY]

I can confirm from my own experience that this happens.

First laptop at work, always plugged in (except for maybe one or two hours a week). After two years of use (maybe a couple more from a previous employee) the battery lasted 30 minutes.

Personal laptop. Mostly plugged in (except when traveling maybe 3-4 weeks per month) but with the charging at 80% capped (it's an option from the manufacturer). Almost 10 years later still holds around 1-2 hours (disclaimer: I don't use this laptop anymore except for occasional tests)