There are some people in the indie scene that can.
Yes, but this isn't the indie scene Roberta Williams was in. The indie scene as we know it didn't exist. If it was now, Roberta Williams probably COULD have made her early games by herself. Guess what? She didn't get to lean on RPGMaker like you do. Programming wasn't so simple at the time (if you even consider RPGMaker programming).
Also don't forget companies have time pressure.
Yes they do. Sierra On-Line was a company. A company founded by Roberta Williams, which became one of the biggest game companies at the time. Again, how does this mean women can't make games?