This still wouldn't change anything.
The thing that requires TATs to be that long is -for >95% of flights- the passengers. Only in very few cases, where there is excessive amount of baggage to be loaded (where there normally is no more space for cargo anyways), the ground time is that long for non-PAX reasons.
In a regular turn around, baggage and cargo loading takes a lot less time than passenger loading.
This goes for bulk loading (loading every piece by hand), and a lot more for container loading.
Example:
An A320 full cabin takes ~12-15mins to empty (considering a regular scheduled flight with relatively routined PAX; +50-100% for charter/holiday PAX) and 17-25mins to fill (again, +50-100% for charter/holiday PAX), while off and onloading of containers/pallets on all available spaces takes roughly 15 minutes combined. If you have 2 loading crews with double loading equipment you can cut that time in half.
Example 2:
A B77W full cabin takes 25-40mins for deboarding, depending on number of jetties (again with relatively routined PAX, add time for tourists as above) and 35-60mins for boarding, depending on number of jetties (again more time for unroutined travelers).
Off and onload of all positions, which can only be filled if you have a LOT of cargo (15-40tn, depending on volume:weight ratio) is about 50-60mins (less with double loading crew).
Additionally at some airports fuelling is not allowed while PAX are boarding/deboarding, baggage/cargo loading is still allowed however. So you can add some time for fuelling between the PAX times as well. On a B777 uplift is about 2000kgs/min -> ~4mins of fuelling per each hour of flight, on the A320 you have an uplift of 800-1200kgs/min -> ~3mins per each hour of flight.
I assume you see where this is going?!
Of course these examples are void, if you have 20 PAX and 15 tons of cargo, but those flights are not the day to day operations.
And don't bring up RYR as an example, they try to have as little baggage as possible (by charging extra), and treat GH staff life workhorses, and push things quite far in terms of legality concerning work-safety, airport regulations and other restrictions.
cheers,
Jona L.