Am engrossed in my work--but anxiety about everything gets me down ... My plan is to stay on until the end of June ... The symphony is making great strides and I must get it finished while I am still in full spiritual vigour. It's strange, this work's conception.Over the next few years Sibelius alternately promised and reneged on delivery of the work. In 1933 its imminent premiere was even advertised in the press as the crown of Koussevitzky's offering of all the symphonies in Boston. But it was not to be. Though it seems likely it was finished--Sibelius even refers to having finished it many times--he never allowed it to appear. In 1945 he consigned a great basket of manuscripts, which likely included the Symphony No. 8, to the fire and in later years refused to even speak about it.
His whole life Sibelius was plagued with self-doubt and anxiety regarding his work. The genesis of the Fourth, Fifth and Sixth symphonies was a difficult struggle for him and at first he labeled the Seventh a "symphonic fantasy." It was the very importance of the symphonic medium that daunted him and finally, appeared to have silenced him. His admirers and colleagues like Koussevitzky, the American critic Olin Downes (a huge supporter of Sibelius' work) and many others could never grasp what the problem was, why Sibelius could not release a piece he had worked on for so long and one which was so eagerly awaited by the musical world.
Sibelius was an intensely private man and became more so in later life. He did not share his inner turmoil with the outside world and only partially with his immediate family. I have speculated in the past that perhaps Sibelius' silence stemmed partly from the currents in the musical world seemingly flowing away from his kind of writing. Stravinsky and Schoenberg were more and more the stars of the musical firmament. But after reading more of Sibelius life and work in Guy Rickards' monograph I suspect that was not the cause. Perhaps it was simply an overwhelming depression combined with the consequences of massive alcohol consumption--Sibelius was certainly an alcoholic, though he did manage to control his drinking for part of his career at least--that finally caused his creative energies to flag.
But what a tragedy! What we would not give to hear Sibelius' final "strange conception" after the astonishing delights of his previous symphonies! But alas...
Here is his one-movement Symphony No. 7 in a performance by the Swedish Radio Symphony conducted by Esa-Pekka Salonen: