Arsen7: But I was wondering - why in the real life did NASA decide to go with Apollo?
According to NASA sources it was simply a matter of the available techs and resources, which made it more feasible for LOR to achieve JFK's deadline, than direct ascent or EOR.
The decision between direct ascent or some kind of rendezvous was made quite early:
https://history.nasa.gov/SP-4203/ch2-4.htm Now when talking of the decision between EOR and LOR is when things get interesting.
Note the lack of any justification for the dismissal of the EOR concept in this NASA page, which would probably have meant establishing a space station and might have had an even greater effect on technology development (also according to this page):
https://www.nasa.gov/centers/langley/news/factsheets/Rendezvous.html This paper sounds very true to the internal dealings of a government organization in the 60s, and the personality of von Braun, which was ultimately (according to many historians) the one that settled the argument with his endorsement of the LOR concept over EOR:
https://repository.si.edu/bitstream/handle/10088/29808/Neufeld--WvB%20and%20LOR.pdf