No, it does not mean the women could not have told the disciples later; this can be established two ways:
- Grammar
- Narrative context
Grammar
The aorist is sometimes referred to as a "simple past tense", which is true...but incomplete.
An aorist indicative is a fairly straightforward reference to a past event, but the aorist need not necessarily indicate whether an action is complete or ongoing. The Greek word ἀόριστος, from which we get the name of the aorist tense, means "indeterminate" or "indefinite" (source).
There is no reason grammatically why the sentence could not continue to the effect of: "they didn't tell anyone along the way to see the disciples". Most Greek manuscripts of Mark do in fact continue the story, indicating that the women's silence was temporary.
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Narrative context
The ending of the Gospel of Mark is a subject that evokes many passionate responses. The Textus Receptus (and most Greek manuscripts) include 12 more verses after Mark 16:8; the Critical Text ends the book of Mark at 16:8, and a few other manuscripts provide yet more alternative conclusions to the story.
There are 4 main schools of thought:
a. 16:8 is the original ending of the Gospel of Mark
b. 16:20 is the original ending of the Gospel of Mark
c. 16:8 was not the originally intended ending of the Gospel of Mark, but the author was unable to finish
d. 16:8 was not the original ending of the Gospel of Mark, and the original ending has been lost
I have a video on my channel examining the evidence in greater detail, wherein I use grammatical, narrative, and historical arguments to evaluate why option b is rejected by most (not all!) modern scholars, and options a & c are very unlikely. I build a case therein for the plausibility of option d.
In any event, option a implies, and options b-d require, that the women fleeing in fear isn't the end of the story.
It's fashionable (and haughty, and condescending) to assume ancient audiences were too thick to notice gaping plot holes in a story. This is hardly a valid logical or scholarly argument (and keep in mind that in a world with lower literacy rates, story-telling & story-recollection played a more prominent role in people's lives). The fact that the author knows about the women's experience at the tomb demonstrates that the women did not stay silent forever.
If we accept option a (I do not), the women didn't stay silent forever. If we accept any of options b-d, the women didn't stay silent forever. I suggest then that the clearest interpretation of the text is that the women hurried off and didn't stop to tell anyone along the way.
Appendix--The ending of Mark's Gospel
Much of modern scholarship has rejected the originality of the last 12 verses of the Gospel of Mark, principally because:
- They are absent from Codices Vaticanus & Sinaiticus
- 16:8 is the point of divergence among the various differing endings of Mark that exist in the manuscript evidence
- There are uncommon words used in the last 12 verses of Mark that aren't used anywhere else in the Gospel
- The transition from verse 8 to verse 9 is awkward, and some see that the last 12 verses do not adequately complete the storyline of the rest of the Gospel (see quote below).
The authors of One Gospel from Two - Mark's Use of Matthew and Luke suggest:
Throughout the Markan account of the Passion Narrative we have noted
time and time again that Mark has carefully argued, sometimes
painstakingly, that Jesus' predictions are fulfilled. This is not only
a narrative device. Fulfillment of Jesus' prophecies is theologically
crucial to Mark. If this is the case, why does Mark have Jesus predict
(twice) he will be reconciled with the disciples in Galilee (Mk 14:28,
16:7) but offers no proof of fulfillment? Furthermore, Mark says that
the women are to tell Peter that Jesus is risen, but they do not do
so...if Mark ended at Mk 16:8. In our judgment this raises a serious
question about the authenticity of this ending [the shorter ending]. In a very fundamental
way the longer ending [vss 9-20] in its present form does not complete
the Markan story line in a fully satisfactory manner either (ibid p.
334; see more extensive discussion of the topic on pp. 328-335)
In writing the above, Peabody, Cope, and McNicol acknowledge the inadequacy of the ending at 16:8 (option a above), but that the ending at 16:20 (option b above) leaves some matters unresolved as well. (And that even as skeptical a scholar as Bultmann was constrained to conclude that 16:8 doesn't work as the original ending). Their mentor, William Farmer, on the other hand, concluded that 16:20 was the original ending.
I do not believe it is possible, on the basis of the extant evidence, to prove whether 16:20 is the original ending of Mark's Gospel or whether there was an original ending that was lost. I suggest, however, that there are very serious difficulties (see my video linked above for further discussion) to proposing 16:8 as the original ending.
If Mark 16:8 is not the original ending of the Gospel, the oddity addressed by the OP finds straightforward and unambiguous resolution: not only did the women not stay silent forever, but Mark explicitly tells his audience that they shared the message.