tubes have to be replaced, as often as yearly if left on 24/7 for devices operating at their power limits - well designed SS doesn't have a comparable wear out mechanism - derating, protection from ESD, operating in a dry environment without ionic contamination, many SS transistors, diodes, op amps used in discrete headphone amps can be expected to work for several human lifetimes - NASA and the Military have standards, models of lifetime/failure rates - you may need to replace Electrolytics at decade(s) intervals
I do believe some of the Audio Critic points may be overdrawn, insufficiently qualified - but still a model of somber propriety compared to the rhetoric of 90%+ of the Audiophile press promulgating the "Myths"
it is always ironic to see attacks on "conventional engineering" understanding of cable effects, digital Audio theoretical underpinnings delivered to my desktop over Mbaud ADSL modem pushing the bits over a few thousand ft of 1/2 century old telephone twisted pair
RedBook is arguably "too close for comfort" to human auditory limits - but large studies still haven't shown it insufficient for Music: Hartley, Nyquist, Shannon, Wiener formulation of Information Theory and its current application to Audio really "works"