I came 2nd in my local writing club's competition last year, with a story 23 years old. This year I came 1st (£100) with a story 20 years old. I've entered newer stories in the past, with little success. Have I got worse as a writer over the years?
Clare Pollard in an article pointed out how an interest in translation can lead to escaping the limitation of local trends. She admits to admiring Somali poems "which can seem clumsy ... the politically charged rhetoric ... the seeming bagginess, the extreme alliteration, the shifts in address, the digressions" thinking that "they just use techniques which are currently deemed 'unfashionable' on Creative Writing courses."
Literature has its fashions. The "From Apocalypse to The Movement" module at Warwick looks at one lurch in style. Of course there are many parallel tracks of development happening at different speeds, but if you're the wrong type of writer for your era you'll be fighting against the tide.
Because culture isn't frozen in time, one option is to wait for it to change. I notice at local writing clubs that my conventions don't always match those of other members. Sometimes mine are more literary - in particular I puncture the sense of immersion - but often I'm just out of step. My guess is that the literary styles that I employed years ago are now becoming mainstream, and the styles I currently use were popular 20 years ago, and may well be so again.
The moral, as usual, is not to throw away old stuff, even if it's been rejected a few times. Old pieces may need tweaking though, especially if you're going to transplant them to the current era. Mobile phones in particular are plot-busters.