To give them more credit, their operations seamlessly transitioned to (subscriber-free) radio as well, without losing subscribers:

> In the 1920s, the company was granted the right to establish the first radio broadcasting station in Budapest, which began operating on 1 December 1925.[11] The combined operations were now known as the Magyar Telefon Hirmondó és Rádió. The services were offered in parallel for some time, both on radio waves and telephone wires. By 1930, Telefon Hírmondó had started other services, and it had 91,079 subscribers.

It seemed like their telephonic service already had advertising, though.