I'd just suggest trying a beer where you make a healthy starter, say 2-3L. Compare to beer direct pitch. Then you'll have your own evidence. I've done this a couple of times and come back to the starter.
Primary #1: Ice Shanty Bock #2: Empty
Secondary #1: Berry Rhubarb Wine #2: Black Currant Wine #3: Empty
Kegged: Hidden Lake Nut Brown, Border Crossing Vienna
Bottles: 2H IPA III, Carmel Apple Cider, Spruced Winter Warmer, Surly Bender clone, Big 50 Barleywine, Framboise Lambic, Dark Belgian Strong, Russian Imperial Stout, Sparkling Elderflower Wine, Barolo Wine, On Deck: ??