Actually a ratchet clause is a clause where usually the annual rent review is either CPI or % which ever is the greater. At Market review is at lease option to renew for a further lease term specified within the lease contract. The ratchet clause does not apply. So you are incorrect, as market reviews are at options usually.
The optimal word in all of that is "usually". It may be usual for your Leases, but it is certainly not in ours.
Our Lease alternates every year between fixed and 'at market'. We have multiple 'at market' reviews during the term of the Lease.
Also, don't know what your ratchet clause states, but ours is very clear. Once the rent is at a certain level, it never goes down. The very worst scenario is the rent rises 5% every year.
For example, if the 'at market' review takes place, and the rental market is deemed to have tanked, and say is evaluated to have gone down 20%, it automatically rises 5%.
If on the other hand it is deemed to have risen 220%, like for instance now
.....then of course the ratchet clause is not necessary and it increases 220%.
As with everything, it all boils down to the very specific and minutae wording and phrases within both the specific contract and over-riding governing laws.
Words like 'generally' and 'usually' and 'normally' and my personal favourite 'standard' have no bearing whatsoever.