I measured this by years and not starts because it was a landslide. Looking up exact starts and comparing them would have been pointless.
Michael Waltrip went 16 years with out getting a win.
The closest drivers I could find were Derrike Cope (8 years), Lake Speed (8 years), Joe Nemechek (6 years), Jimmy Spencer (5 years), etc... I skipped over a lot of names on the all time win list because I figured if I didn't recognize them, they probably did not race for decades! And, in order to beat Michael Waltrip in this category, someone would have had to race for a long time!!!