It is definitely a question about "wind quality" yes, AND skill
For me, when 10 knots I ride with an 8 or 9 m2 normal LEI wavekite, so hardly never drop it.
If I do, I most often have to drift ashore and relaunch (no swimming), as hardly any gusts so no chance of relaunching.
When 7-9 knots, I use a light 1 strut LEI, and here I might have to swim/drift, if there are lulls and I make a mistake - which happens on occasions, rare though.
As only if a mistake, because such LEIs can hang in this wind no problems - in less wind than possible to ride, and you can always loop the kite to keep it flying while you drag ashore, even if it drops to 5-6 knots.
Would estimate I drop it 1 out of 15 sessions (the 6-7 knot sessions), so yes it happens.
I dont ride close to shore (okay, not REALLY close as I usually ride quite close), as sitting on the board with the kite on the water, drifting slowly to shore, is just fine.
In 5-6 knots, max 7, I use an 11 m2 racefoilkite, and sometimes I have to swim, after having packed it, after it goes down.
It is soooo much on the verge to impossible in the lower end of this windrange, that it can easily drop if even a small mistake - or a lull where even tucking the frontlines isnt sufficient, or it might collapse.
Always ride close to shore in this supermarginal wind with foilkites, so only a short swim - and sometimes I can pack it down where I can stand on the bottom, WAY easier of course
Quite rare I use the foilkite, 1 out of more than 30 sessions where it is needed, as there is very often at least 7 knots where a LEI is just fine and no risk you end up having to do a packdown
But WHEN I do, in sub 7 knots, the chance/risk that I get a swim after a packdown, is 1 out of 6 sessions I can see in my log
In short, when 6-8 knots I drop my LEI 1 out of 15 sessions, when 4-7 knots I drop my foilkite 1 out of 6 sessions.