Spectre is a much more complex issue. It is more of a "I would never thing of that" thing. Looks like there were people at the security community talking about it even 10 years ago, but it is certainly hard for knowledge to spread to chip designers - most of what security people study would be noise for them, and even the security people mostly ignore those.
Do you have a different source for that?
To see why that toy example is insufficient, consider that you could simply execute the load directly without putting an exception in front of it and you would be able to read the value.