But if Luke inherited potential from his father, as opposed to deriving it purely from belief, then there's a biological factor
One which needed no explanation from Lucas to the movie going public of 1977-83 in the form of blood tests, so it was not
needed with Anakin in TPM, either. Further, Luke may have inherited potential from his father, but he had to be trained to open his closed mind to pure belief--
faith--in order to access it, otherwise he would be no more adept at sensing / accessing / controlling the Force as he had been on Tatooine. Obi-Wan's
"Stretch out with your feelings" /
"Use the Force, Luke! Let go, Luke!" was Kenobi stressing Luke break his reliance on what he believed he could control physically, which prevented him from connecting to / using the Force. Aboard the
Falcon, he had to stop relying on his sense of sight to "see" the remote with the blast shield covering his face by opening his mind to belief in that intangible power which--contrary to Solo's mocking--controlled everything. In the Death Star trench, again, Kenobi implored Luke to stop relying on that which was tangible--the X-Wing's targeting computer (which failed all others only minutes before) and believe in the Force--the higher power--to allow him to do what no programmed device used by a pilot ever would ever be able to.
On Dagobah, again, Luke is repeatedly told to
believe (have faith) in the Force--to divorce his mind from the secularized perceptions of the physical world in order to access, bond with and use the Force, otherwise he would fail time and again by clinging to essentially a disbeliever's perspective of / approach to all acts as being a measurable, physical effort in the corporeal world, leading to one result, or, as Yoda so pointedly put it,
"That is why you fail".