Did anyone else besides Jesus ever restore a person from blindness? If not, why?
You are right that scripture does not, so far as I can tell, record any instance of anyone other than Jesus restoring sight to the blind (and this He apparently did quite a bit in fulfillment of the prophecies about Him as the Messiah: Lk.7:21; cf. Is.42:7; Matt.11:5; 12:22, etc.). Matthew 10:1 does say that the twelve were given authority to heal "every sickness and disease" - that may or may not have included restoration of sight. We do have instances of the dead being raised by men other than the Lord (Elijah, Elisha, Peter, Paul), so this is indeed an interesting point you make. It may be that such instances just were not recorded (as indeed most instances of healing were not put down in scripture for obvious reasons of space; cf. Jn.21:25). But there is also the fact that it is only in Jesus that our spiritual blindness is removed (2Cor.3:12-18). Jesus made a definite point of contrasting the restoration of physical sight to those who believe with the spiritual blindness of those who possessed physical sight (Jn.9:1-41). As the One who is the Light by which we see (Jn.1:4-9), the restoration of human vision is a very powerful symbol of accepting the truth which, once accepted, not only removes our spiritual blindness but brings us to eternal life (cf. Ps.146:8; Is.29:18; 35:5). If there were any others who restored sight, it seems likely to me that the Spirit has chosen for this reason to preserve in scripture only the instances performed by Him who is the Light of life, through whom, though we were blind, we now see.
For details about our the course of our Lord's earthly ministry including His use of miracles and related issues, please see the following links:
The Course of Jesus' Earthly Ministry
Jesus' Cursing of the Fig Tree
Miracles of the 144,000
Miracles of Moses and Elijah
Yours in the glorious Light of life.