Often the difference in equipment is not going to be apparent until you push that equipment further toward its limits. Viewing or producing images for the web can be done with virtually any camera with good results. 
If say a selection of gallery images from here were to be taken and printed at 20 x 16 for an exhibition then i believe differences would begin to show. I have seen this happen at another web site where an exhibition of printed work was shown. Members submitted files which were printed and mounted for them, though they did have the option to submit prints and /or mount their own. 
I'm not suggesting that a printed version is any better or worse than the web images we view, but it is the reason why many professional photographers choose the equipment they do. 
Another major reason for some equipment being more expensive than others is how robust it is in use. When used in a working environment equipment suffers a lot of constant use and abuse, it has to be able to withstand this which is often why pro equipment is made the way it is and is subsequently more expensive.  An amateur photographer doesn't necessarily have the same needs .

In conclusion from my experience it is better to have the equipment that is able to produce the results you want to achieve and this does not mean buying the most expensive if it is not needed.  
I don't use my camera equipment everyday, all day - I don't need to have expensive pro equipment that can do this. When the weather starts to get inclement  I like to be indoors where it is warm and cosy - I don't need expensive pro equipment that is weather proof.  I have the time and inclination to take care of my equipment because it is more important to me than a single shot - I don't need expensive pro equipment that can withstand the knocks it will get when the shot is more important than the equipment. The list goes on and on but I think you get the point .............

One other point I would like to express is I believe smaller compact cameras have their place and excel in some areas where larger more expensive equipment can't keep up.  One of these areas is bug shots - it is far easier and you get better shots imho using a compact camera for this genre than you do using a dslr . One of the reasons is the speed you are able to react and the positions which you are able to get the camera into to make the shot which brings me onto another area where compact cameras excel - spontaneity of capture . Photography is about two main things: light  and a moment in time. When it comes to a moment in time speed and versatility is king and compact digital cameras excel in this. You can hold them in virtually any position with one hand and see what you are shooting. They can be whipped out your pocket and the shot made before the person with the dslr has managed to get it to their eye, let alone thought about if they have the right lens on for the shot and what settings they should be using. This works on a more artistic level too where iin recent years small digital comapcts have brought lots of new images to photography and we see less of the more tracitional shots from the same old angle and pov that we have all seen so many times before. 

Well I've bored everyone enough now if you bothered to read this at all. Should have just said: ' 'Horses for Courses'  and left it at that 

  

And every one said, 'If we only live,
We too will go to sea in a Sieve,---
To the hills of the Chankly Bore!'
Far and few, far and few, Are the lands where the Jumblies live;
Their heads are green, and their hands are blue, And they went to sea in a Sieve.

Edward Lear
http://www.nonsenselit.org/Lear/ns/jumblies.html