I recently answered a question related to Catholicism and then one for Pentecostals/Charismatics, so now I will attempt to complete the trifecta and answer a question on behalf of Protestants, if that is even possible. There are obviously many denominations of Protestants with differing views on the Eucharist.
Protestants feel that Catholics have taken the doctrine far beyond what the New Testament teaches. For most Protestants, communion is a ritual meal of remembrance of Christ’s sacrifice on the cross. The Lutherans go further and say that the benefits of Christ’s death and resurrection are distributed through communion and that there is a unity at the most profound level of the bread and wine with the body and blood of Christ. The Catholics go even further and claim that the bread and wine is fully changed into the body and blood of Christ,
Protestants point to 1 Cor. 11:26 to show that the purpose of communion is to proclaim the Lord’s death till the time he returns. The elements in themselves don’t have much material effect on anyone and certainly shouldn't be counted on to sustain life (inedia). In the early church, communion was celebrated as part of meal and was not an elaborate ritual.
Both Luther and Calvin denounced the Catholic practice as idolatrous and the latter in his Treatise about relics (1543) tried to persuade Protestants not to follow what he felt was the cult of relics. He showed that Christ is preferable to anything of his that may have somehow survived through the centuries. He also demonstrated how it was idolatry to worship anything that was not God himself. Protestants would pretty much universally condemn the worship of any object (even a part of Christ's body) whether created or preserved by a miracle or not.
Most Protestants don’t see anything miraculous in the communion elements which could potentially explain why they never see such miracles. It usually requires expectant faith to experience miracles. Many would agree with Curiousdannii's comment that he would view such miracles with extreme skepticism. That could be interpreted to leave the door open at least to the slight possibility that such a miracle could be shown to be true (though most occurred too long ago to authenticate). But even if it were scientifically proven that the host had been supernaturally altered, that would not prove the validity of universal transubstantiation. The fact that human striated muscle fibers and blood are found on a host here and there does not prove that every host is so transformed upon ingestion, for example.
Finally, there are some Protestants who come alongside their Catholic brothers and sisters in search for common ground. If Jesus had not died and been resurrected, there would be no communion at all. Faith in him and what he did for the benefit of all mankind is the basis of salvation. If he has miraculous power to change bread into the body of Christ, he can change a repentant sinner into a sanctified believer.