I think sensor size is less important than people think it is. Yes, you get increased tonal range, but that is one of the few benefits.
Any good compact with a 1/1.17 sensor will be able to take photos of approximately the same quality at web/screen resolution. One of the, if not the biggest increase I see with bigger sensors is better noise control at higher ISO. To compare, a samsung TL500 is rated at $450 new (can be had for <$300), a Nikon d3100 is rated at ~$800 new, but can be had for ~$625. The samsung keeps noise well controlled up to iso 800, and images are usable at iso 1600. At iso 3200 (the maximum) images are generally considered unusable. Meanwhile, the d3100 can take excellent pictures with minimal noise up to iso 6400. If you compare images at say, iso 400 of the same subject at the same time in natural light, you will see roughly equal quality, with maybe a little bit of clipping on blacks and whites in the TL500 from the sensor. However, for the masses the tl500 will take an equal picture to the d3100. Of course I'm asuming the d3100 is using a kit lens (18-55mm) and the samsung has its amazing 24-72mm f/1.8 lens. To put that into perspective, assuming each lens was bought for a dSLR, the nikon comes with a ~$200 lens, where the samsung's would cost in the vicinity of $4000. Now you're thinking, that's absurd! lenses are not that expensive for this kind of thing! Well, they kind of are. You see, a 24-72mm f/1.8-f/2.4 lens doesn't exist at dSLR size, mainly because to hit a reasonable pricepoint with that low of an aperture is not possible. The closest thing I could find is
a Canon 15-85mm f/3.5. Now, 15-85 is a much greater range, so deduct some points there, but f/3.5. Reaching into f/2.4 territory would cost you about $2,200 for a telephoto lens like this. Apertures as low as f/1.8 is only done in prime lenses, although it's usually f/1.4. Perhaps it's more fair to look at this
nikon 24-70mm f/2.8 lens, which is $1800.
In short, reaching down into f/1 range with telephoto is insanely expensive, mainly because keeping lenses sharp at that low an aperture with telephoto capabilities is neigh on impossible.
tl;dr it's complicated, but a fantastic lens can make your sensor size matter a bit less.
disclaimer: I own none of the equipment used here, and I should really have used B&H or some other specialist, but linking to amazon is just very easy to do for me.