1 you use 1
2 (or even 3) you use "a couple"
A few is almost always > 3 and one could argue that upper limit 15
So, 10 years to 50 years
2 (or even 3) you use "a couple"
A few is almost always > 3 and one could argue that upper limit 15
So, 10 years to 50 years
15 is too high to be a "few" except in contexts of a few out of tens of thousands of items.
Realistically I interpret this as 3-7 thousands of days (8 to 19 years), which is largely consensus prediction range anyway.
That said, I think people are possibly overanalysing this very vague barely-even-a-claim just a little. Realistically, when a tech company makes a vague claim about what'll happen in 10 years, that should be given precisely zero weight; based on historical precedent you might as well ask a magic 8-ball.
But the mere fact you say 15 is arguable does indeed broaden the range, just as me saying 1 broadens it in the opposite extent.