Granted in this use the drop off due to distance is very minor but depending on the fibre its self you can have max runs from 150m to 1000m (OM1-5). Light does loose a little intensitiy every time it hits the side so there is a natural drop off.
OMx is grades of *multimode* fibre used within building backbones and short distances i.e within racks at data centres typically < 500m. Multimode fibre is
not used in external telecoms and especially not in any sort of PON or point-2-point topology used in FTTP.
Singlemode fibre is exclusively in terrestrial telecom networks, subsea links, etc. Since the early 2000’s singlemode fibre has been optimised to have zero water-peaks and dispersion shifted. It can sustain terrabit capacity up to hundreds of kilometres with the right optics. It’s a completely different animal.
When a fiber cable is bent excessively, the optical signal within the cable may refract and escape through the fiber cladding. Bending can also permanently damage the fiber by causing micro-cracks
The key is excessive - that is effectively broken. You can of course over bend fibre, beyond its limits during install or later. In the main though, spine cabling once installed it’s not really moved about. Drop fibres serving the premises from CBT and inside/out fibre from CSP etc. are typically G.657.x rated, so called bend insensitive fibre. In any event if the light levels are within the specified limits the fibre is good. It matters not if the subscriber is 20m from the node or 2km.
Openreach don’t OTDR every single customer connection, but they do test up to the splitter and often a port on the CBT, so if the cable from the splitter was going to be damaged it’s likely to be picked up at this point.
do wonder what these small tollerances will look like in 10,20,30 (or longer) years when even faster speeds are offered as they will not be an issue now but may be then which is why the closer the better imho.
There’s singlemode fibre which has been laid and in use for decades and is perfectly serviceable and useable. An enormous amount of fibre was deployed before and around the millennium by eager and enthusiastic global telecoms companies. In fact it was over-provisioned, however the happy legacy is that today much of that fibre continues to be used for cross country connectivity by the companies which succeeded those that went bust in the dot.com and telecoms bust of the noughties.