> It also requires light sources to have actual sizes, a bit of a departure from traditional point light sources that have a position but are treated like an infinitely small point in space
You don't wait for the ray to bounce into a light. Lights are typically sampled directly at each bounce point in a path tracer. If you waited for the beam to hit a light it would take a crazy amount of time (100k+ samples for complex scenes) to converge.
> how far you can trace them before giving up
You can use Russian roulette techniques to get unbiased sampling of arbitrary length paths.
> The crux of the problem is that with a path tracer you are locked into an all or nothing approach...
There's many more subtleties into getting convergence than simply 'tweaking quality settings', eg. volumetrics, types of lighting, types of material, denoising etc. Also it's MUCH more difficult to get a realistic result with simple raytracing than the author says.
> is it the future of high quality offline rendering?
Pathtracing has been used for almost all offline VFX rendering for a very long time now (although there's some new interesting developments in using rasterization for production now)