Reading an answer under this question, I found one interesting point: the use of the future perfect with the verb possess. My question is rather simple. Consider:
By that time, I will have possessed three cars.
(NOTE: It doesn't have to be "By that time", it might be something like "By the time I retire", "By the time my son graduates", a more idiomatic phrase such as "By then", etc.)
Will I still own the cars by that time?
In my opinion, it could be interpreted as either a) my possession will be over (so the perfect tense), or b) the possession will keep building up and by that time I will have already owned three cars.
Are both interpretations possible?
Note: I think this is a good example on the use of stative verbs with perfect tenses. Possess, in my opinion, is a stative verb. Saying "By that time, I will possess three cars." would be enough already; thus, saying "By that time, I will have possessed three cars." explicitly might be used to emphasize the sense that the cars will have already, by that time, gone.
Best Answer
tl-dr: With perfect aspect, current/ongoing state is ambiguous. In your sentence, the time phrase may condition our view of the ongoing state.
I would interpret your original sentence as follows: at the point of retirement, you may or may not own one car, but you won’t concurrently own all three (in that case, you would have used ‘will possess’.)
Perfect aspect does not say anything about the current/ongoing state – that is the domain of the continuous aspect. Thus current/ongoing state is ambiguous, although we may infer something about it from the situation or other factors. For example,
It’s not clear if you currently own one, but we can infer that you don’t, because otherwise you would have just used the present simple. This is an inference, because the current state is ambiguous.
Different time phrases used along with perfect aspect may define (or imply) whether the action is ongoing or not. For example,
Clearly you still own it.
Clearly you don't own it anymore.
It seems that with your original sentence, it’s the time phrase that conditions our view of the state of possession at the point of retirement.
Addendum: Concerning your idea about stative vs active verbs, I’m not sure if that’s relevant here. Look at the following examples.
Being married is a state, getting married is an action. But in neither case do we know if Alan is currently married.