This article misses the mark in my opinion. The 4800H is just as capable, often outperforms the 4900HS depending on the cooling solution, and is available in several models today. The writer is clearly looking for the 4900HS in a premium laptop, which is a segment currently reserved for Intel.
No systems integrator would ever take the risk of committing to a new chip architecture for their flagship premium segment out the gate, which is why we currently only see the Renoir chips for mid-tier laptops like the Asus Zephyrus G series, Lenovo Yoga/Ideapad 7 series, etc.
This will only change when we see a systems integrator finally take the leap of faith and put the Renoir chip in their premium flagship, like a Dell XPS, Lenovo Yoga 9, or Asus Zephyrus M series.
This has nothing to do with exclusivity agreements, and everything to do with marketing and product management.