I do recall reading that the British Military Baker Rifle of the early 1800's had two different loads that they carried. One was a fast loading paper cartridge, and the other was a "tighter" loading ball for long Range accuracy. Now IMHO, and I'd have to do more research - I think they were able to load both without a short starter, just as I can load a patched .433 ball and a patched .437 ball in my .45 GMB Rifles without a short starter and the .437 by all rights produces the better grouping... However, they will never produce the groupings that a patched .440 and .445 ball will produce in those same .45 cal GMB Rifles.
When one thinks about it, a frontiersman / homesteader / soldier, who was raised on the smoothbore and carried it into adulthood, the littlest increase in accuracy from smoothbore to a rifle even with a loose fitting patch and lead ball combination which loaded easy just like their smoothbore did, well,,, to them this had to be an improvement from their point of view at the time I would think.
And I'll add (just my opinion),,, who from that/those time periods would be willing to give up that little extra time in loading / reloading with a short starter (especially if you were in an Indian fight or any other kind of conflict you may find yourself in) - as speed is everything. Now I'm not saying that our frontiersmen carried two different size balls - but I bet they carried the largest ball they could that would still slide down the bore with a patch with ease,,, and I expect that when target shooting time came around that same undersized ball they normally used may very well have found a second patch around it going down that bore - and at that point they'd have to have some sort of way getting that combination started, be it a short starter of some sorts or the handle of their knife (like I've seen done before).
Just all conjecture of course - but reasoning is sometimes all we have to go on.