I was also a bit surprised that there was so little crossover with Doctor Who, which was in its early years at the time Thunderbirds was being made. Several of the lead voice actors appeared once or twice in Who, but the only person from behind the scenes whose name I spotted was Dennis Spooner, who must have gone straight from his job as script editor for Verity Lambert to writing six episodes for Gerry Anderson, possibly even doing both at the same time. I scrutinised the summaries of Spooner's Thunderbirds stories (for the record, they were Day of Disaster, End of the Road, Vault of Death, The Mighty Atom, The Imposters and Cry Wolf) to see if I could spot common themes with The Reign of Terror, The Romans, The Time Meddler and the second half of The Daleks' Master Plan, but I'm afraid I drew a blank.
I was surprised to read that the two 1960s films did so badly, considering that the Peter Cushing movie versions of Doctor Who, which came out at about the same time, performed at least respectably. I suppose that the large screen does puppets very few favours, where at least human actors still look like human actors when in close up. Perhaps there were failures of marketing as well.
Now that we are almost half way from 1965 to the stories' setting of 2065, it is interesting to consider how Anderson's vision of the future is at variance with our reality. One point that really struck me was the impossibility of International Rescue keeping its location and methods secret. In 1965, photographs were real concrete objects which could be stolen, confiscated, hidden or destroyed. Nowadays any Thunderbird mission would find itself instantly on YouTube, and Tracy Island would be a popular sight on Google Earth. It's also interesting that the show had non-white characters in it from the start, even if one of them is the villain and the other two, though allies of the Tracy family, are vulnerable to his mental powers.