I don't think it matters at all for road bikes. <duck>
Manufacturers recommendations will be for liability as much as anything else. Mates of mine who are fair weather boys (nothing wrong with that) change theirs every year without fail even though they have done less than 1500 miles or so, they seem to take great pleasure in the task. It won't harm anything will it, £30 a year or so is cheap.
Now, the following is not a recommendation its simply my direct experience (and I have seen inside my fair share of race engines).
I use mine for a 90 mile daily commute, all year round.
My Fazer 1000 has done over 85k now, the last 35k I put on in the last 2 years or so it has never had an oil change as such. It has not had an oil filter change in this time (oops, I do have a new filter, might put that on tomorrow...). So that's 35k, no oil change, no filter change. The caveat being, as with a lot of Gen 1's it does use about 100 or 150 ml each 500 miles (so a week or so depending on if I go for a blast now and then). Thus I am constantly topping it up.
It runs perfectly. Never misses a beat, gear changes are as slick as ever, clutch is perfect (never had to touch it) isn't noisy, doesn't smoke, starts first time, easy on fuel. Took a peek inside, its perfect - cam, gearbox - look as good as could be.
People will tell me that it's crazy, asking for trouble, this will happen, that will definitely happen - but they have no first hand experience, just here-say and "forum wisdom". It doesn't, its perfect, its experience. Someone might say "your talking rubbish, my mate had this that and the other and such-a-thing happened", well in my experience of running high mileage it's just not the case.
The worst thing you can do is run it low/empty of oil. If it at least has some in they its better than nothing, fully synth, mineral, veg oil... Run it low or dry then it will go in a very short space of time.
I use fully synth (Motul 300V or lately Silkolene Pro4 as it was on offer at the time) but i do tend to get it cheap or free (from my bro) but the difference is negligible really. I have also (in an attempt to slow the oil consumption) used a thicker oil than recommended, ran 4 litres of that for many thousands of miles, no issues. It did slow the consumption a bit... A lot of people would think it would cause massive, life threatening problems (even for anyone remotely related to you - or had simply heard you ride a bike) but the reality is its fine - I probably did more miles with it than a lot do for the careful ownerships of their bikes.
With that in mind, I might be selling it soon, any takers? Religiously maintained...