Tina Louise *had* no real career possibilities other than that of many other actresses at the time whose roles depended more upon fact their curves were in proper places, and they weren't not so bad to look at.
That being said Miss. Louise was like many others of 1970's and so on was mainly a jobbing "television" actor/actress. Though TL did land some small roles in films like Stepford Wives.
https://www.imdb.com/name/nm0001481/
Saw TL on a "Cannon" episode a few weeks ago; she played an undercover vice cop who teamed up with Frank Cannon after getting roughed up during a prostitution sting operation. Acting was "ok" for episode television, but it wasn't as if the lady was going to be doing major film or theatrical roles.
Suppose TL wants to play the victim actress "why is my beauty and great body such a curse....", like Marilyn Monroe, Jane Mansfield and others who were pigeonholed into roles in theory because of their looks.
Miss. Louise was in her thirties when doing GL; by the 1970's she was going into her forties, and that alone may have been responsible for "killing" her career.
Then as now on both large and small screen roles for actresses begin to dry up as they go > 30, and certainly in their 40's and above.
Concept of *MILF* (sorry, but it is what it is) just didn't exist for Hollywood back then. So actresses above a certain age regardless of looks found themselves being offered mostly roles as mothers, matrons, middle aged wife, etc...