While there may be a need to have a bit more than 2 due to chance deaths, that does not alter the situation. In a population of 1000 those having the mutation will be 1/1000 of the population. In a population of a million those having the mutation will be 1/1,000,000 of the population even in cases where the population increases. Therefore the neutral mutation will not spread and there will be only a very small chance of a 2nd, 3rd, or 4th mutation which will be helpful occurring. The likelihood is that the mutation will dissappear because of the fact that the overwhelming amount of mutations are detrimental.
Initially, yes.
In a population of a million those having the mutation will be 1/1,000,000 of the population even in cases where the population increases.
No, look up "Genetic Drift".
Therefore the neutral mutation will not spread
Again, this is an invalid assumption. True, there's no guarantee it will spread, but it is as likely to spread as it is to die out.
Look up "Genetic Drift" -- there's a surprisingly good chance that a neutral mutation will spread to the entire population.
and there will be only a very small chance of a 2nd, 3rd, or 4th mutation which will be helpful occurring.
You're making a fallacy there. Sure, there's a "very small" chance that a particular "2nd, 3rd, etc." mutation will pile onto a particular individual with a given mutation, but you're missing that other members of the large population will have their own unique mutations from the current or past generations. This makes for a large pool of mutations to be "worked with" as new mutations occur in the population.
Also, as the population interbreeds, the various mutations in the population get "mixed and matched" very rapidly, the "2nd, 3rd, etc." mutations don't have to occur in any direct descendant of the individual with the "1st" mutation. If they occur *anywhere* in the population they can get shuffled together at any subsequent generation.
Sexual reproduction is a very powerful process for the bringing together of multiple mutations which occurred very separately in space and time.
The likelihood is that the mutation will dissappear because of the fact that the overwhelming amount of mutations are detrimental.
Now you're changing the subject.
First you were talking about the fate of neutral mutations, suddenly you try to say that "the mutation" will "disappear" because it's likely detrimental. No, it isn't, you were specifically talking about the neutral ones.