Seems to me that Westinghouse did manufacture their own vacuum tubes. Here is a snippet from an interview:
"The war ended and then came a time when things were going very slowly and progress was not to my liking. I got an invitation then from Westinghouse. Westinghouse by the consent decree after at about 1930 had to stay out of the receiving tube business. But by 1950, they could make receiving tubes again. Westinghouse wanted to make not only receiving tubes but more power tubes, cathode tubes, pick-up tubes and what have you — the whole shebang! So I accepted the job and became chief engineer of the newly created Westinghouse tube division. I had a marvelous time because I always wanted to build something from scratch. I hand-picked the engineers, I built up a patent department for the tube division and so forth. It was wonderful. We started to work first in Bloomfield and then the location was changed in 1952 to Elmira in New York State, where they built a new factory. After several years the aims of the company changed. The management in East Pittsburgh had different ideas. There was a slump of business, and I thought of leaving the company. I got an early retirement that was accepted, and I was free. Then I looked around. I had a few offers, but RCA invited me and discussed things with me and I felt inasmuch as I knew RCA and most of the personnel very well I would be more effective there than if I would go somewhere else and start from scratch. So I became a consultant for RCA, worked on semiconductors on germanium, silicon, on methods of making transistors. I had a grand glorious time."
Here is the link to a lengthy interview with a tube pioneer: