Name an old prominent watch company that HASN'T been brought back from the dead

I guess Universal Geneve technically still exists, but considering what the active web-page is offering, would be more merciful to pull the plug...

So they are.
(although don't sense much in common between the old design language & new...)

I live a few miles from "Elgin".

It is a bit complicated as @TimeODanaos says!

At it's 1973 general meeting Helvetia decided to dissolve and it closed. On the same day Silvana SA changed it's name to Helvetia SA! Both companies were part of SGT at the time and the board members of both were basically the same.

So the old company of Helvetia is gone but since 1973 Helvetia watches have been sold by the renamed Silvana. They are still going and are part of a Jewellery company based in Austria though they officially have a registered office in Switzerland. I don't know how many watches they make but they usually have a few new Helvetia branded and vintage other brand watches for sale on Chrono24. Chrono24 seem to have changed how they display the seller info, it used to actually say 'Helvetia International' as the seller.

https://www.chrono24.com/helvetia/helvetia-quartz--id8159048.htm

If you look up info on the company it says date formed as 1923 which is when Silvana was formed. Example below:

https://gb.kompass.com/c/montres-helvetia-sa/ch060973/

They are a bit all over the place with their history. Their, very out of date, website says 'since 1880' which would be wrong even if they were the original Helvetia as La Generale was formed in 1895. They then sell this model below which seems to be a celebration of 50 years from 1895 to 1945. I'm assuming the watch is supposed to be similar to something from 1945 but looks to have been produced in the 1990s, 1280 Euros if you want one.



So the name Helvetia still just about continues but the company is actually the old Silvana SA. and they are really a Jeweller in Vienna who sell a few Helvetia branded watches that look like they were produced in the 1990s along with their other stock

Here is my history of the Helvetia name: https://www.helvetiahistory.co.uk/history

I've seen both "Elgin" and "Gruen" watches in the Wal-Mart jewelry section in recent years.

As for brands that have yet to be zombie-fied, Wakmann?

http://www.wakmann.ch/index.php

Well that's a damn shame.

Waltham, both US and Swiss versions

Didn't Titus buy out Waltham long ago, before Titus was sold off to the Chinese?

I actually don't know.