Regarding "How do you account for the many high quality and rock-stable vacuum tube products now being manufactured?"---
The point is that there are NOT many vacuum tube products now being manufactured. World-wide, receiving-type vacuum tube products now comprise near-negligible numbers. It's purely limited to some hi-end audiophile products and guitar amplifiers, and that specialty market is simply infinitesimal. This state accounts for the fact that ALL of the traditional large corporate tube suppliers exited the business decades ago. Currently, tube production is limited to a small group of foreign opportunists who are sufficiently agile to extract profit by virtue of low cost manufacture and high selling price. This is characteristic of the last phase of life in a dying industry. Hey, it's dead technology; may it RIP.
The point is that there are NOT many vacuum tube products now being manufactured. World-wide, receiving-type vacuum tube products now comprise near-negligible numbers. It's purely limited to some hi-end audiophile products and guitar amplifiers, and that specialty market is simply infinitesimal. This state accounts for the fact that ALL of the traditional large corporate tube suppliers exited the business decades ago. Currently, tube production is limited to a small group of foreign opportunists who are sufficiently agile to extract profit by virtue of low cost manufacture and high selling price. This is characteristic of the last phase of life in a dying industry. Hey, it's dead technology; may it RIP.