It's all a matter of bandwidth and impedance. Let's say for example you had thin (and I mean "thin") pure gold wire cable, say 5 metres long, connecting your video but it was not rated at any more than 2 megahertz bandwidth. On the other hand you had copper cables rated at 10 megahertz bandwidth. The gold cable having virtually no resistance (impedance) will let a very pure signal through but it will not be complete, because of its limited bandwidth, and may look like just a poor signal. On the other hand, the copper cable will let all the required signal through, only it may not be as pure as the gold cable, because of the natural resistance of the copper. In this case, both signals may look as bad or as good as each other, but in reality, they each have merits and demerits compared to the other.
What you really need is a cable that has the required bandwidth and as little resistance as possible. I see lots of claims about cables and their chemical compositions and wonder if my basic school science was a waste of time, because some of them claim that certain elements help in the purity of the delivered signal and therefore, cost the earth, while what I was taught way back in school, tells me that that is crap. Remember the 3 methods of transferring energy...
1. Conduction
2. Convection
3. Radiation
We know for instance that gold is better than copper, which is better than say aluminium or iron for conducting electricity, don't we. I am not going to name names, but I was recently looking around at a shop and picked up some video cables, costing in the 100's of dollars and I saw some of the ingredients in the cable and I thought "Naaa, it can't be true - that would only work against its conductance". It may however inprove its bandwidth, which may well aid it, in the long run...
Most of us may not even know what bandwidth is or how it works. It really, in simple terms, means getting as much intelligent signal down that single wire as possible, within the lower and upper frequency limits of its design or properties. Example.... Imagine a single lane road being the wire. It's lane width is its bandwidth. Now imagine that the vehicles which travel along that road are your pulses of video signal. Now imagine you are in your car, on that road, all alone. No troubles here because you have the whole road to yourself. There's no impedance/resistance... Now imagine hundreds of others on the same road with you and you are at the very back of the line of cars. Your fastest speed is detemined by the slowest car infront of you, remembering that this is a single laned road - No Overtaking..!!! Now imagine you car magically turned into a whopping great 40 ton truck fully loaded and much wider than the road and entering a tunnel. Bammm. Of comes the sides and top of your truck. It just can't make it through, complete, so you lose half your vehicle because you can't slow down or stop on this road, so your truck looks rather sick when it arrives at the depot... The same sort of thing happens in your wires. It depends on either/both of those important factors to do the job effectively. Your eyes may not perceive the finer parts of the wires design.
At the end of the day, was you see is what you see, and if you are satisfied with the image, you can't really argue and may feel enitrely happy, but you may not be seeing the larger picture, so to speak, by skimping on price. On the other hand, I am sure, you don't have to spend megabucks on over-rated wiring. I bought some of the genuine component Monster Cable and while I did notice a huge difference from the $5 cables they replaced, I have since looked for, bought and made my own cables out of good connectors, and highly, well rated coaxial cable available from electronics shops, and they appear to be every bit as good as the "Monsters" I spent about 5 times the money on. No matter where you go though, you will find that quality components like connectors and wire etc, are not cheap. Simply put - If you want quality, you have to pay for it,, OR,, You only get what you pay for... Seldomn are those rules of thumbs breakable...
Good quality cables do NOT have to be gigantic in size, but size does help.. In a coaxial cabe, equally important is the relationship between the inner conductor and the out braiding, which need to be a certain percentage of there widths arpart from each other to maintain the needed inherent rated impedance, in ohms.. If this distance alters, you get a change in impedance, once again resulting in signal degradation. Even the length of the cable can have a direct bearing on the final output. The wrong length may result in "standing waves" at given frequencies (wavelengths), which can cause feedback and signal loss.
There is an exacting science to cables but most of us don't need to know it. When you make antennas and use radio transmitters like Ham Radio, as I do, you need to know exactly what you are doing or you wind up with a pile of melted parts, and if you think your DvD recorders, or you TV's are expensive, try Ham Radio gear for size....
Hey, if you are happy, so be it... Be aware though, that better cables do a better job and there is no way around that. However, not all cables are created equally...