I want to make an additional comment as the your above quote makes my point.
Reagan was just as good at public speaking in 1976 as he was in 1980 and he was considered far more electable in 1976 than 1980 because of his age. Even with the things in his favor, he couldn't get past Ford by his was a sitting incumbent.It wasn't until the Democrat-Lite Republican incumbent was out of the way that Reagan got his shot.
That is the whole problem - the Democrat-Lite Repbublican incumbents are mucking up the works - they block anyone better from getting past them.
If a man like Reagan couldn't even beat Ford in 1976 then that shows you the power that sitting incumbents have in the primary process.
Intentionally giving up and hoping to come back to win the day in the future is a strategy for crackpots and losers.