Timber price is going up around the world. Years back there was also a big disruption to OSB board production, due to big fires in North America. However... OSB board is simply much more efficient use of timber and has therefor been quite stable and reliable source of building material.
Common misconception about SIPs is how much timber is required to assemble the panels together. When we get excited about the SIPs in general, often we want to push SIPs further and ideally not use solid timber at all, but it doesn't work this way, there is still some timber in assembly of SIP panels. But you can be clever in how you use SIPs to minimise use of solid timber.
In principal we often specify studs @600mm crs when we design with timber frames; top&bottom plate, maybe a double top plate when we have larger rooms and need a diaphragm, and the never ending discussion about why do we actually need those dwangs/nogs etc... But it appears that the times of studs @600 are long gone, and with more wind and seismic issues, more adventures designs, taller walls, bigger rooms and large openings, we have more and more timber in what remains of the wall:
Here is another picture of a wall that has lots of timber to support the loads. Actually double stud @300-400mm, multiple studs to form the corner and also the dwangs, that apparently are not needed structurally. But even if we remove the dwangs, there is still quite a bit of timber in such wall.
And while the SIP wall also needs a CAP plate (double top plate; due to the loading), when we remove SIPs, there is very little timber in this wall (picture on the far right). Connection between three SIPs is done using an insulated SIP spline. The perimeter needs a single 45mm timber stud to close the panel. But the load is actually supported by facing board of the SIP panel, not the studs.
So.. is building with SIPs therefore more affordable? I guess this is completely different question, mostly due to the variable price of SIPs available locally. But when it comes to use of solid timber. I think SIPs are pretty smart solution (?)