Using GoDuke measurements and calling the five players who started the most games the "starters":
2010: 6'2, 6'5, 6'8, 6'10 (Miles Plumlee started 24 games to Brian Zoubek's 16 starts): Average: 6'6.6" (now that's a real Devil average)
2018: 6'3, 6'5, 6'6, 6'10, 6'11: Average: 6'7.0"
2022: 6'2, 6'5 (Trevor Keels started one more game than 6'6 AJ Griffin), 6'5, 6'10, 7'1: Average: 6'7.0"
2023: 6'2, 6'6 (Jacob Grandison, though maybe 6'5 Tyrese Proctor or even 6'8 Mark Mitchell), 6'7, 7'0, 7'1: Average: 6'8.0"
Even if you count Zoubek in 2010 and Griffin in 2022, and drop 2023 an inch by saying Proctor is a starter instead of Grandison, this year's starting team is the tallest Duke starting team in at least 15 years (probably a lot longer than that).