I am assuming that these details are taken from online trees - I personally think a lot of assumptions/guesstimates have been made.
First of all, there is no marriage of a John Kingsbury to an Elizabeth in Little Waldingfield (LW marriages are on familysearch).
Secondly, I note the online trees state that John was born 1764 Great Waldingfield BUT there is no age given on John's burial details!
I think that John was older than has been assumed - a John Kingsbury married an Elizabeth Orvis 23/10/1781 Kersey (just a hop and a skip away) and 3 children baptised there:
Mahale bp.2/7/1782, bur.20/8/1783
William )
Elizabeth ) both bp.14/9/1783
then nothing - no burials in Kersey for them after 1783 so they clearly moved on.
Think they are the couple who ended up in Little Waldingfield by 1794 but can't say if any other children born between 1783 and 1794 or where they were in that time.
I think it has just been 'assumed' that because they are in LW by 1794 that they were newly married (ca.1792?) and the best 'fit' age-wise is the John bp.1764 Great Waldingfield. I personally don't think that was him at all. Just my opinion for what it's worth.
At the end of day, no-one knows how old John was when he died 1798, and there is certainly no marriage between a John and Elizabeth ca.1792 Little Waldingfield (or anywhere else in records online for Suffolk around this time). With the family I found at Kersey 'disappearing' from there after 1783 they seem a likely family to have ended up in LW.
Annette