The tunnel is going in (possibly); the idea is indeed to reduce traffic stops and the general stink and noise near a major tourist attraction. Not everyone is in favor of such projects, as the comments sections seem to indicate.
The tunnel would be nice ,but the country can’t afford it at the moment.
It is purely a vindictive vanity project.
Widening the road is cheap, this would allow the site to be investigated then the tunnel built when we can afford it.
As was settled with the prevous government before the current redevelopment began.