But for the last 20 years they haven't been as close.
That was before consoles established decent online shops. Now they have them and they run summer sales and winter sales etc they are way more competitive.
That's why I "these days" because I appreciate it wasn't always like that.
Some examples on Loaded. (prices maybe vary a little on various key sites)
Crimson Desert. £42 on pc. £42.99 on Xbox
Resident Evil requiem. £29.99 on pc £35.99 Xbox
007-first light. £52.99 on pc.. £48.99 on Xbox.
Lego batman legacy of dark knight. £39.49 pc. £42.99 Xbox.
Not too dissimilar really.