Among the possibilities:
1. Lewis sought the promotion because he thought the prestige of the position might improve his chance of gaining a permanent professorship, either concurrently with the post (which had only nominal duties of giving three lectures a year) or subsequent to it.
2. Lewis needed the extra money that came with the position, being in financial straits over the cost of dealing with Janie Moore's dementia and declining health, which eventually led to her being institutionalized for the last few months of her life.
3. Lewis who had strong views on poetry, especially modern poetry, wanted the bully pulpit the
Professor of Poetry provided.
Of these, the first might seem more likely, except that there doesn't seem to be much precedent for it having so benefited previous holders of the chair. The second is complicated by the fact that I'm not at all sure it came with any money at all -- Grevil Lindop in his new biography of Charles Williams says the position was unpaid (THE THIRD INKLING p. 410). But then he's speaking of the mid-forties, and things might have changed by the early fifties, when Lewis ran.** The third almost certainly played some part, but I think it's impossible to say how large a part. But if so, why did Lewis leave the campaigning in the hands of the irascible Hugo Dyson?
I'd like to get a better read on this, because the Professor of Poetry-ship actually looms large in the Inklings story. Two Inklings, Adam Fox and John Wain, actually held the position. Lewis ran for it, narrowly losing what seems to have been a bitterly contested election. Williams thought he had a good chance at gaining it when he retired (I think this unlikely, but in the event he died before ever running so we'll never know). So too did Barfield, who in a few late interviews wistfully mentions having thought it was all set up for him to take up the post upon his retirement, only to have the prospect fade away (did Lewis really think he cd get Barfield elected to the post?)***
So, a puzzle. Presumably over time bits and pieces will fall into place, making it easier to understand this part of Lewis's life. But for now, for me it continues to be an odd episode.
*so far as I know, there's nothing to prevent someone from being re-elected, but I don't think that's ever actually occurred -- at least, it hasn't in the whole twentieth century (before that most folks held the post for about a decade).
**Nowadays it brings in around seven thousand pounds a year, according to wikipedia, which is more like a large honorarium than a salary.
***actually I think Barfield wd have been a brilliant choice, but an extraordinarily unlikely one, given his low profile; he only came into his own in his old age, by which point all his Oxford contacts were gone).
THE WIFE SAYS
If he took the post, what are the chances it'd help him get his own poetry published?
(JDR: I hadn't thought of that, and given how badly Lewis wanted to be a major poet, and how he'd republished his awful early book DYMER the year before (1950), I think this may well have been a major factor)