I came across this picture many times while doing some reading. This picture states the facts that a recessive deleterious allele will become dominant in offspring born of 2 carriers of the deleterious allele. But it seems to have removed the other possible outcomes.
Aa + AA = { AA, Aa, Aa } the assumption is that the deleterious allele is more likely to be passed on rather than the dominant beneficial allele? According to probability shouldn't the chances of offspring with AA and Aa be equal?
Aa + Aa = { aa } and where have the other possible outcomes gone? Aa + Aa = { AA, Aa }. Yet again in terms of probability the chances of producing offspring with Aa should be higher than aa and AA.

Now lets define a new diagram: (only inbreeding, no crossbreeding)

First Stage :
AA + Aa = { AA, AA, Aa, Aa }

Second stage :
AA + AA = { AA, AA, AA,AA }
Aa + Aa = { AA, Aa, Aa, aa }

Third stage :
AA + aa = { AA, Aa, Aa, aa } but if natural selection were to be present aa wouldn't get a chance to reproduce no? **
Aa + aa = { Aa, aa, aa, Aa }
**Over time, natural selection weeds deleterious alleles out of a population — when the dominant deleterious alleles are expressed, they lower the carrier's fitness, and fewer copies wind up in the next generation

Already by the 3rd generation we see that the AA individuals are more abundant than individuals with Aa and aa.
I am assuming that we can compute the outcome of genetic drift using probability.

Another point to ponder : what if there were a recessive beneficial allele? What outcome would we get then?