I feel I should point out here that all electronic components have a predicted life span - an MTBF or mean time between failures. This tends to be in a bell curve distribution, with the vast majority of parts lasting a medium amount of time - the peak of that curve is the given lifespan of the component. This would mean that even the most expensive charger is going to have a limited lifespan and whilst more expensive units may have higher precision components it's unlikely that their MTBF will be significantly better than the midrange components used in the average charger. It therefore stands to reason that in a unit like a Li-ion battery charger that is going to be fairly basic (mostly off the shelf standard resistors, capacitors, IC's and Optoelectronics) the cost of repair would be prohibitive compared to cost of replacement so a charger costing £100 plus would not use components of significantly longer lifespan, in which case cost per unit becomes a deciding factor, cheaper units that can acheive the same function as more expensive units will simply outsell and therefore prohibit investment and creation of more expensive units.
In other words the £100 "Super" charger will not sell as it's dominant features can be matched at a lower price point by the "Mass Market" charger - Witness the Blu-6, a 6 bay bluetooth enabled charger that should in theory dominate the market amongst the "POTV set" vapers - but doesn't, the cheaper less featured 4 bay chargers dominate as they can perform the same main function - charging batteries at lower cost...