Could be that they come across as too negative and angry at all times and may be better advised to outline their own priorities and plans if in government rather than constantly rattling the cage from the outside.
No point trying to dismiss polls - recent polling in advance of elections here have been very accurate. SF (like all parties) delight in good polling numbers, using them to call on government to call a general election and a sign that people want change and will downplay poor numbers, saying "it's not what we're hearing on the doorsteps" and "the only poll that counts is on election day" etc.
Lot of things can change in three weeks though - if say Marylou McD performs well in media as she did before last GE, that 23% could move significantly upwards again before local/Euro elections.
Likewise, if on her current visit to USA, she is as muted on Gaza situation as she was on Paddy's day visit, compared to SF's strong pro-Palestine, anti-Israel policy in Ireland, they may lose some of their younger voters who feel very strongly on the conflict.
Putting it in context dear. Joe Stalin was General Secretary of the Communist Party from 1922 to 1952. Eamon Devalera was leader of Fianna Fail from 1926 until 1959 when the job of President of Ireland became vacant
As I said, longevity doesn't mean lack of democracy - but you probably still don't get it
