I don't understand the point you're trying to make. Are you claiming that if Mojo was open source earlier, everyone would still be using the old versions for a long time? I don't buy the claim that a pre-1.0 language only a few years old without widespread production use is comparable to one of the most widely used languages on the planet that had been around for close to two decades at the time of what you're describing.
Even if I did think that was a comparable precedent, that still doesn't address the more direct point I made about marketing the language at all if this was a concern. What does being closed source do to prevent people from running old versions of a compiler to avoid updating their code?
Even if I did think that was a comparable precedent, that still doesn't address the more direct point I made about marketing the language at all if this was a concern. What does being closed source do to prevent people from running old versions of a compiler to avoid updating their code?