That he was a born storyteller who sold his birthright for a pot of message. (See the King James Version of Genesis 25:29-34 if you do not understand Shaw's pun.)
The same can be said of Heinlein. Wells was a Fabian Socialist, while Heinlein was a libertarian. For me, the archtypical Heinlein novel is Glory Road, the first two thirds of which is a rollicking adventure story, told with wit and humor. In the last third, Heinlein gets on his soapbox to proclaim his political message, and is almost unreadable. I should also mention the vast amount of gratuitous sex, which reads like the fantasies of an overactive 14-year-old boy.
Heinlein's first hit was Starship Troopers. I read this in an English class I took while I was in college, after having been in the army, including a tour in Vietnam. The professor knew that I was a combat veteran, and asked me what I thought of the novel from that viewpoint. I replied that Heinlein obviously knew the military, but had no experience of combat, since no one who had been in combat could have written that novel. I looked him up, and discovered that I was right: Heinlein had graduated from the US Naval Academy at Annapolis in the late 1920s, but had been invalided out of the navy for tuberculosis in the 1930s. During WWII, he held an engineering post at the Philadelphia Navy Yard. Interestingly, two of his coworkers were Isaac Asimov and A E Van Vogt.
Johnny Rico, the hero of Starship Troopers -- Heinlein does not have protagonists, he has heroes -- is the sort of character who gives cardboard characters a bad name. Any novel that has verbatim lectures from courses in "History and Moral Philosophy" makes me think that the author has other motives than just telling a story. He glorifies war, and his philosophical ramblings are libertarian idiocy at its worst.
Don't even get me started on Time Enough For Love, in which Heinlein makes it clear that he agrees with Harlan Ellison that "love ain't nothing but sex misspelled". Heinlein spends hundreds of pages on love as eros and exactly two paragraphs on love as agape (selfless love -- "No one has greater love than this, to lay down one’s life for one’s friends." John 15:13), which he dismisses as essentially irrelevant. Remember that the high priestess of libertarianism, Ayn Rand, wrote The Virtue of Selfishness, which rejects altruism as "weak". I have described Heinlein's philosophy as "by Hugh Hefner out of Ayn Rand".
Every female character in TEFL wants to have sex with Lazarus Long, including his mother, and all but one of them do so. The image of Lazarus Long's mother giving him a lock of her pubic hair as a keepsake still bothers me, over forty years since I read the book.
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