No Error Correction
Can we just clear something up once and for all. There is no error correction ( should I put that in capitals ? ) on HDMI. None , nothing , nada.... this is one way raw data transfer there is no error detection let alone error correction. If digital was all it took for your ' it either works or it doesn't' approach then why do we have error correction on network comms , clearly they 'shouldn't need it' after they are 'digital'.
Common sense should lead us to conclude that in the absence of error correction, the only defence against data corruption is cable assembly and cable components , both of which are likely to escalate in cost the more attention is given to them.
What is in the favour of those who advocate cheap cable is that most people only need a 1m cable and over those distances data loss is likely to be minimal, however in cable world length is not the only issue since most problems arise at the junction points i.e. the plug and the socket and the plug and the cable.
Clearly there is a law of diminishing returns here, I doubt a £20 cable is going to be twice as good as a £10 cable , but I don't have any difficulty believeing that it is a better cable and if I choose to by it on that basis then surely I should be entitled to do so without being called an idiot.