Generally, the displaced threshold is not because of the load of touching down, but because of clearance of obstacles. When landing, where you are aiming to land, and a standard glideslope, puts you over obstacles at a certain height. In some cases if you landed on the very end of he the runway, that would cause you to collide with (or have too low a margin of safety) over obstacles before the runway. The displaced threshold moves the glideslope further forward, allowing for better clearance over obstacles.
Source: Advisory Circular 150/5300-13B Airport Design, 3.5.3 (https://www.faa.gov/documentLibrary/media/Advisory_Circular/...)
When it is impractical to locate a threshold at the beginning of the runway, it may be
necessary to apply a displaced threshold. A displaced threshold reduces runway length
available for landings in one direction. The portion of the runway prior to the displaced
threshold typically remains available for takeoffs. Depending on the circumstances
surrounding the displacement, operations from the opposite runway end may or may not
be affected. Refer to Appendix H for related information on declared distances.
Generally, a runway threshold displacement provides:
1. A means for obtaining additional RSA prior to the threshold.
2. A means for obtaining additional ROFA prior to the threshold.
3. A means for locating the RPZ to mitigate incompatible land uses.
4. A means for obstacle clearance prior to the threshold.
5. Increased arrival capacity with certain parallel runway approach procedures. See
FAA Order 7110.308, Simultaneous Dependent Approaches to Closely Spaced
Parallel Runways
Glossary:
RSA: Runway Safety Area
ROFA: Runway Object Free Area
RPZ: Runway Protection Zone
Note that all of the given reasons are for clearance of obstacles or various other mandatory safety areas based on clearance from taxiways or other runway traffic, not for durability of the runway.