If that were true, I think the extra 40 hours of training to get the Instrument Rating, not to mention passing what is regarded as a notoriously difficult skills test, is a complete waste of time and money...
Which, to a large degreee,
is true if we are talking about equipping a pilot for flying in the European enroute system.
But if one is to regard the IR as a mini jet type rating, or perhaps a means of sorting the men from the sheep, then the IR is doing a great job.
The amount of theoretical knowledge and raw instrument flying competence that is actually needed, in any plane that is equipped anywhere near adequate for the job, on top of currency on type and type specific systems knowledge (which isn't taught) is far less than one might think.