I ride a bike and drive a car so am fairly objective and can see both sides.
You're riding a small engined bike. Very quickly it will bore the hell out of you and you'll be hankering for something bigger. When this does happen (and it will), you will be trading you awesome MPG figures for something more like an average family car. For example my DL1000 got 32mpg, my ZZR1100 gets 50mpg.
Not too bad at all. But then consider that whereas a car can typically carry 5 people, a bike will normally carry 1 or very occasionally 2. Divide the MPG figure by the number of people being transported and then the eco credentials start to look less favourable.
Practicality is also a big compromise on a bike. Whilst it may take me 10 minutes less to get to work on a bike, by the time I've factored in kitting up and de-kitting to the journey time, the car actually wins.
Want to give a friend a lift? Car wins unless your friends all have their own PPE and carry it with them on the off chance you'll give them a lift.
Going to a gig/show/movie? Enjoy sitting through that in your gear balancing your lid somewhere safe. Failing that, spend the entire evening wondering if you backbox will contain anything when you get out.
Going to Ikea? Givi luggage is good, but it isn't that good!
Snow? I've ridden daily in snow. It's possible, but is sphincter clenchingly scary.
Cost? Bikes are cheaper than cars mainly, insurance isn't necessarily. For your putput it is, but get to 600cc bikes and it evens out or swings the other way.
Add to the cost of the bike the money that you can (should) buy to protect yourself, then work out what you need more than one of and add that on. Then security items etc etc. It's not cheap when done properly.
Safety. You can ride as safely as humanly possible, but it's everyone else you need to be aware of. Your chances of being in an accident aren't significantly higher than when driving a car, but the likelihood of being killed or seriously injured are massively increased. It's fact. Rationalise it how you see fit, but know that it is a far bigger risk than being in a car.
That said....
I get more pleasure from 10 minutes on a bike than 10 days in a car. Driving for me is functional, riding is something to look forward to.
I'd seriously suggest more people try riding, if only to see why so many people are willing to overlook the negatives I have given. also so they can get an idea of how it feels to have to treat every other road user as someone with the intent desire to kill you!