Is there technical debt in some old systems? yes. Is there technical debt in systems written 3 months ago? absolutely. They are both equally likely to have at least some technical debt - taking a system already running in production, perhaps written in cobol 20+/- years ago, even with some known problems - and paying someone to rewrite the entire thing in the newest framework de-jour, imo, is just (if not more) likely to introduce new bugs and new technical debt as it is to solve any problems with the old system.
Sure, if the system no longer meets your business needs, and no one can figure out how to fix or maintain it - then by all means, consider an upgrade - but if it is not (seriously) broke - don't fix it.