On top of what others have said, this actually doesn't apply to RSA at all. There are ways to factor the prime-product used in RSA faster if you believe the 2 primes are close together[1], so any good RSA key generator should be picking primes that are far apart (when I wrote a toy key generator for a class I just tried to make the second prime more than twice the first), and this "conspiracy" only applies to consecutive primes. As you get further away from the original prime, you get less info about what the last digit could be.
[1] https://en.wikipedia.org/wiki/RSA_%28cryptosystem%29#Faulty_...