I don't post here often, but the few times the subject of THE TIME TUNNEL has come up, the opinions were often on the negative side - and I get that. Irwin had his ways and always opted for "cheap". I was still fascinated with the idea of time travel.
And let's face it - LOST IN SPACE was truly a mess, particularly most of that second season.
I love the Irwin Allen shows. The Time Tunnel is my second favorite behind Voyage.
Irwin Allen always wanted his series to be edge-of-your-seat excitement, but he was also hampered by network budgets. They didn't 'get' sci-fi at all and just wanted his shows to cost the same as Gunsmoke each week. So Allen was forced to cheap things out by hiring second-string writers as his series went along.
I don't think "cheap" is accurate. He spent money, but he front-loaded his seasons with bigger budgeted effects episodes and then when they got to the back 9, that's when you'd see the really cost cutting episodes. Voyage did that in the color years - be he also did simultaneous shooting on a few 1st season shows to catch up on both time and money. He'd rely on small cast episodes (skeleton crew episodes or, as he called them "one man shows"), stock footage to cut production time and so on. Voyage was a very effects heavy series. He relied on stock model shots, but every SF show did. Star Trek included.
The Time Tunnel's format had the movie footage baked into the concept. Otherwise, it never would have gotten done. The format changed 2/3 of the way through to chase ratings. LIS didn't use much stock footage, but stuck to a soundstage 98% of the time and had much smaller and lower run guest casts. Land of the Giants is where he want all out on money. Too bad it wasn't a very good series.
Irwin ran reports, did surveys and got a ton of data to see what people wanted. That and the budget generally dictated what we got. For Voyage, I loved it. Lost in Space, nah.
I should also point out that his first series, VOYAGE TO THE BOTTOM OF THE SEA, started out with lots of cold-war espionage stories that were middling in the ratings. But on those weeks where he threw in a monster, the ratings soared. So in an effort to keep the ratings high, he just had his writers do more monsters.
Well, yes and no. Voyage did great when it debuted. It was a solid hit for the first half of the first season, But then The Man From UNCLE was moved opposite and that sucked away Voyage's audience.
The following season, once they went to color, Irwin - still chasing the fads - made Voyage much more spy heavy. And THOSE episodes did poorly. The second season, now moved to 7pm Sundays, struggled when it came back. Even with terrific episodes like Jonah and the Whale, The Cyborg and Escape from Venice. The thing is, Voyage did Man From UNCLE poorly and that's not what kids were watching for. They had spies everywhere. They wanted what made Voyage unique. Then they upped the promotional spots, focusing on the monsters and action, so when they aired The Phantom Strikes with a ghost story and that brought the audience back. Most of Voyage's most highly rated episodes in the second season were in the back half. Monster/SF shows like Deadly Creature Below and the superb Leviathan were among the lowest rated. But, again, in that back half, episodes were padded with stock footage from The Enemy Below, The Lost World and prior episodes because he blew his wad early.
So when they were going into the 3rd season, Irwin felt all monsters all the time was what people wanted. And for a while, he was right. The series, after a weak premiere showing, brought in good numbers. Those lasted through past the halfway point. Then the back 9 were just in the cellar. People had enough and the late season episodes were really threadbare.
As for the writers, yes, people like Peter Packer and William Welch were hacks and not expensive. But they were also cooperative and that's what the issue was. Irwin was never going to pay Quinn Martin money for his writers, but the main issue was he was a tyrant. Willian Read Woodfield and Allan Balter couldn't deal with him and left for Mission: Impossible after contributing some great scripts (and a few not so great). But then they got in the weeds with M:I producer Bruce Geller and walked out of that show after a few seasons - so I think it was a Woodfield problem (he was a bull of a man apparently). And eventually, nobody really good wanted to work with him. And even if they did, the scripts were gutted by the story editor and Irwin to remove person al scenes to keep the focus on action, monsters and more action.
Right. But like Voyage to the bottom of the sea I don't think TT would have gotten The Great Vegetable Rebellion bad ...

....TT and Voyage had their goofy episodes but nowhere on the scale of a talking carrot.

....
Well Voyage did have a talking Lobster Man and a Terrible Leprechaun - which is my vote for worst episode of the series.