Commercial success with high book sales, successful theatre productions and a string of film adaptations, backed by astute stock market investments, allowed Maugham to live a very comfortable life. Small and weak as a boy, Maugham had been proud even then of his stamina, and as an adult he kept churning out the books, proud that he could. Yet, despite his triumphs, he never attracted the highest respect from the critics or his peers. Maugham attributed this to his lack of "lyrical quality", his small vocabulary, and failure to make expert use of metaphor in his work. In 1934 the American journalist and radio personality Alexander Woollcott offered Maugham some language advice: "The female implies, and from that the male infers." Maugham responded: "I am not yet too old to learn."
Maugham wrote at a time when experimental modernist literature such as that of William Faulkner, Thomas Mann, James Joyce and Virginia Woolf was gaining increasing popularity and winning critical acclaim. In this context, his plain prose style was criticized as "such a tissue of clichés that one's wonder is finally aroused at the writer's ability to assemble so many and at his unfailing inability to put anything in an individual way".
For a public man of Maugham's generation, being openly gay was impossible. Whether his own orientation disgusted him (as it did many at a time when homosexuality was widely considered a moral failing as well as illegal) or whether he was trying to disguise his leanings, Maugham wrote disparagingly of the gay artist. In Don Fernando, a non-fiction book about his years living in Spain, Maugham pondered a (perhaps fanciful) suggestion that the painter El Greco was homosexual:
"It cannot be denied that the homosexual has a narrower outlook on the world than the normal man. In certain respects the natural responses of the species are denied to him. Some at least of the broad and typical human emotions he can never experience. However subtly he sees life he cannot see it whole ... I cannot now help asking myself whether what I see in El Greco's work of tortured fantasy and sinister strangeness is not due to such a sexual abnormality as this."
But Maugham's homosexuality or bisexuality is believed to have shaped his fiction in two ways. Since he tended to see attractive women as sexual rivals, he often gave his women characters sexual needs and appetites, in a way quite unusual for authors of his time. Liza of Lambeth, Cakes and Ale, Neil MacAdam and The Razor's Edge all featured women determined to feed their strong sexual appetites, heedless of the result. As Maugham's sexual appetites were then officially disapproved of, or criminal, in nearly all of the countries in which he travelled, the author was unusually tolerant of the vices of others. Some readers and critics complained that Maugham did not condemn what was bad in the villains of his fiction and plays. Maugham replied: "It must be a fault in me that I am not gravely shocked at the sins of others unless they personally affect me."
Maugham's public view of his abilities remained modest. Toward the end of his career he described himself as "in the very first row of the second-raters". In 1948 he wrote "Great Novelists and Their Novels" in which he listed the ten best novels of world literature in his view. In 1954, he was made a Companion of Honour.
Maugham had begun collecting theatrical paintings before the First World War; he continued to the point where his collection was second only to that of the Garrick Club. In 1948 he announced that he would bequeath this collection to the Trustees of the National Theatre. From 1951, some 14 years before his death, his paintings began their exhibition life. In 1994 they were placed on loan to the Theatre Museum in Covent Garden.