I had a 62 BSA (way back). It was kick start only. It had to be. No battery. In order to get spark, the magneto (coupled to the crank) had to turn.
I had to rebuild the magneto to make it run when I bought it. It's a twin and I got the timing 180 degrees out when I reinstalled it (had to guess as I had no shop manual). Anyway, I knew to keep my leg straight/locked during kick. The kicker tossed me over the bars, onto the sidewalk in front of the bike. (Fortunately, a 20 year old body can take such abuse.)
I had a different appreciation for the electric start on the 305 Honda after that (never used the kick start on that much).
My 74 Cb550 developed a worn out battery when it was my only bike. Unsure of whether it was the battery or the starter (no part substitutions available from other bikes), I simply kick started it for the daily commutes for another two years...until the battery wouldn't hold enough charge to spark the bike over a weekend of sitting. New battery and the electric start worked fine again.
My Cb700sc has no kicker. It developed a bad starter that became intermittent before failing entirely. It would wait 'til I got 5 or more miles from home before refusing to start, even with a brand new battery. I really missed that kicker on the 550. Being bigger displacement I expected a push start would need two people. But, I finally got stuck out in nowhere with no help in sight. Put in fourth gear and pushed the bike forward from the seated position about 5 ft, pop the clutch and varoom, off I went, and had a nice ride home on the back road twisties. I still wish it had a kicker, but I haven't needed it on this bike since fixing the starter motor.
I know why some bikes NEED a kicker. I just assume it was economics that later designs removed it.
Cheers,