I think that by that time even better technology than hall sensors will be available a lot of TM users had to buy old (i mean really old) CH joysticks just to cannibalize the pots.
CH pots dont match physically in actual Tm sticks, ie Cougar. To adapter is need some machine work, so is more easy for people do some DIY HALL (or MaRS) assembly.
Is need use HALL instead pots? No, but actually these things are more cheap than good potentiometers - Why they appear in Logitech, Saitek and Tm sticks.

BTW - To get CH pots, is no need buy old sticks, just go to CH Spare parts, and buy a new:
www.chproducts.com/shop/parts.html (If every time I advertise this in foruns around the world I receive 0,50$ I would take some beer.)

Manufacturer is CTS:
http://www.ctscorp.com/components/potentiometers.htmSokol1