In some cases we can clean up and re-use an old antenna but the savings come at another cost.
Gain will be less than ideal as the cut of the elements don’t match the new digital frequencys. Close but not close enough to be reliable. Gain falls on a curv down the band so another result can be some good and some bad channels. (Calculated by very well known formula and confirmed by meter readings)
Poor impedence matching also increases the chance of internal noise sources. Adding an additional variable. (Old designs had less rules)
So in short not efficent and added unknown variables makes it a possible but not an ideal choice.
Like towing your caravan with an old rope. It will likely work just fine but when it fail’s we can’t go blame the road or the weather.