it's not really that surprising however, over time
export PATH=$PATH:/foo/bar
would naturally supplant
set PATH=%PATH%;C:\foo\bar
simply because the former has vastly more day-to-day relevance to my life now; the last time i did the latter, it was on MS-DOS
i'm having a bit of a berenstain bears effect with believing that %variable% was surely never how MS-DOS did variable substitution (surely it's some newfangled Windows NT thing?!), but here it is in the MS-DOS 5.0 manual!
From the bitsavers.org collection, a scanned-in computer-related document.microsoft :: msdos 5 :: Microsoft - MS-DOS 5.0 Users Guide and Reference 1991
@hikari i wrote *so many* cursed batch files as a child
if errorlevel my beloathed