[ohohyodafarted]

That ad was obviously an attempt to stave off the likely loss of business that US Steel was going to incur due to the advance of all glass picture tubes that were coming to market at the time that ad was published. IN the end metal tubes lost out to all glass because the all glass B&W bulbs were "turn key" IE: they came ready to use from the glass manufacture. The metal tubes had to be sourced from both a glass manufacture, and US Steel for the funnel. Then the face plate and neck assembly had to be fused to the metal funnel at the crt manufacture. With all glass bulbs, the crt manufacture only had to phosphor the face, install the gun, and evacuate. Metal funnels were destined for obsolescence. They were dinosaurs in the world of technology that advances very rapidly.

In the end all glass bulbs were made possible, due to the huge growth in, and consumer demand for, larger screen tv sets. With the large demand, it became cost effective to tool up the large expensive molds at the glass manufacturer (Corning?) that were required for the mass production of all glass bulbs.

When they perfected frit glass, which enabled the construction of the all glass, 2 piece 21CYP22 color crt, it made the 21AXP22 obsolete, and the era of metal tubes ended. And I say good riddance to bad rubbish. The primary reason for 15GP22's, 19VP22's, and 21AXP22's going bad is the fact that the welds on the metal components are prone to leaking. If frit glass had been avaliable to make all glass color crt's right from the start, we wouldn't have such a limited supply of these rare, early color crt's today.