Eventually hot then failing to finish marathon? (2,3,4,3)
I believe the answer is:
in the long run
'eventually' is the definition.
(I've seen this before)
'hot then failing to finish marathon?' is the wordplay.
'hot' becomes 'in' (both can mean fashionable).
'failing to finish' means to remove the last letter.
'marathon?' becomes 'longrun' (I've seen this before).
'then' with its last letter removed is 'the'.
'in'+'the'+'longrun'='IN THE LONG RUN'
(Other definitions for in the long run that I've seen before include "marathon effort" , "Eventually" , "sooner or later" , "qualified for a marathon?" , "If fit, where Radcliffe will be seen this summer" .)