Well, there really isn't any reason why you shouldn't connect it to the audio output of the television.

As long as it is still functioning properly: no noisy or scratchy controls, no static, pops, or hum in the audio, insulation is okay on the power cord and you are happy with it... why not? You may need to relocate your speakers so they are equally to the right/left of the screen, and run an RCA stereo audio cable between the display and audio system, but that's about it.

Now if you decide at some point you want to have 5.1 or 7.1 surround sound from your DVD or Blu-ray player, then you will need to layout, purchase, and install a new system. But in the meantime you haven't lost anything.

Realistically, 30 years can be pushing it as far as the life of some of the electronic components used on the circuit boards inside the equipment, but B&O (especially 30 years ago) almost always spec'd premium grade components. So, there may not be too much concern there. Just do what feels right to you and not what somebody tells you "need."

The B&O equipment will easily last 30 years, as it's extremely well made stuff, however, you will definitely need DIN to RCA connectors in order to use with your TV set. Determine how much cable length between the TV set and the stereo that you need and look for a 5 pin male DIN to 2 RCA male cable.

be sure that your TV set has audio output jacks on the jack panel in the back, and you will probably have to go into the TV's audio menu and select output to those jacks.

Here is a link that might be useful: 5 pin male DIN connector to 2 male RCA connector

As long as the TV has an audio output. I bought an LG TV and was very surpised to find when I got it home NO Audio output. I should have checked closer before I bought it, but I was more concerned about how many inputs it had.