I agree that the data of a short period of 6 months is not sufficient, but I daresay that if we compare the data of the past 1 year or even 2 years, we might get the same graphical results.
Petroleum reserves are declining at a fast rate, there's no doubting it. Back sometime in 2008 I read somewhere that it might last till 2040, with conservative use, and not after that. Diesel, in its crude form, might be available for the next 5-6 years after that, but definitely petrol will be gone.
As far as synthetic petrol's effectiveness is concerned, we all know how effective it can be.
And there are no news of technologies around to produce petrol en-masse from somewhere. No laboratory breakthroughs, nothing.
I was having a discussion with my Dad on this topic and he told me this - "Beta, most governments around the world have urged auto companies to concentrate on diesels and diesel hybrids a lot more, and to try to phase out petrol cars by 2025. But many auto companies/ developing-underdeveloped countries replied that they would be unable to do this within the period specified due to different reasons, and needed more time. Those particular companies/countries have been given time till 2030."
I couldn't ask for the source of his info but he is an avid radio listener and is always regularly tuned to Deutsche Welle (Radio Germany) and BBC World Service, so there's no reason to disbelieve him.
Putting this aside, just observe the behaviour of most car companies within the past one-two years. The range of discounts and offers available for the petrol versions is notable, which rises to a staggering amount in the festival seasons and the financial year-end. These offers have seen a significant rise within the past few years. No car company is spared from this.
And, it can also be observed that diesel technology is seeing big improvements in the past few years. The refinement in diesel-powered vehicles has improved considerably, and so is the ride quality. As regards maintenance costs, that too has come down, but not as much as to give petrol lovers sleepless nights, yet.
And like evolution, every process is a step-by-step procedure. The trends we see around us do point to the fact that the demand for petrol power is on the decline (however hard the petrol lovers, like me, try to deny it). The entire trend is shifting towards diesel, slowly but surely. People are willing to wait 6 months for a diesel car, rather than pick up a Petrol equivalent in 5-10 days, in some cases even immediately. That says something in itself, doesn't it?
Nothing beats petrol power. And all of us know it. Unfortunately, the passionate petrol-lovers (like me) are slowly receding in number with every diesel vehicle that hits the roads. Even die-hard petrol enthusiasts are going with the times and shifting to the TDIs and VDIs.
It's only a matter of time before the people who matter start to take notice, and take more concrete steps to speed up this process.
Let's face it - the future (not the immediate near-future, but the future) will see diesel hybrid technology.
My case in example - I am on the lookout for a new car, and after a debate on the above topic, I finalised petrol. Then came the decision for the car, and it's the Jazz. Even though I know that things might get tough 15-16 years (maybe even 20 years) from now, diesel can't beat the absolute refinement petrol gives you. Amongst other things.
So petrol it was, even though my Dad protested my decision (and still does it whenever he gets a chance).
What thought process made this decision for me - "at least till my generation is around, petrol shouldn't be a problem, even if the prices go upto 140-150/ltr. I will be 60 years old in 2036, and retired from active service in that year. My career will be over, and that will bring an end to my car-driving days as well. Let the generation after me worry about choices in fuels. As long as I can afford it, let me stick to petrol, however tough the coming days will be."
A small side note - if Honda launches a diesel Jazz within the next 4-5 years, I will be first in line.