How that plays out would be very sensitive to the exact formula for tenure.
Ie. A voting "cliff" where you can only vote after year 1.
Vs votes per years held * shares, in which case an early investor could get entrenched.
Just because someone has held a stock for 20 years does not necessarily mean they are currently interested in the long term. But, it probably points in that direction.
I especially like logistic growth for having slow growth at the start and end, only growing quickly in the middle.
[1] https://www.khanacademy.org/science/biology/ecology/populati...
Example:
Log(years) doesn't have a bound, but is unlikely to cause problems over any reasonable time scale.