Even if that were so, cofty, the writers of the gospel were still willing to die for their writings. You can claim that all the gospels were written by people other than who they are acredited to. However, the time in which they were written was during a period of intense persecution towards Christians.
Also there is alot of evidence of who wrote the gospels. Take for example Luke:
The Muratorian canon (c. 170) states, "Luke, the physician...wrote in his own name what he had been told (ex opinione), though he himself had not seen the Lord in the flesh."
Irenaeus (130-c.200) writes, "Luke the companion of Paul set forth in a book the gospel a preached by him (Paul)" (Adv. Haer. 3.1.1)
Tertullian (c. 160-225) attributes the Gospel of Luke to Luke (Adv. Marc. 4.2.1-5).
The Anti-Marcion Prologue (2nd century) says that Luke the physician from Antioch, Syria wrote the gospel known as the Gospel of Luke.
The Monarchian Prologue (2nd or 3rd century) affirms that Luke wrote the Gospel of Luke.
The oldest manuscript of Luke, the Bodmer Papyrus XIV (p75), dated about 175-225, attributes the Gospel of Luke to Luke, using the title "The Gospel according to Luke."
It is reasonable to conclude that the Luke was the author of the Gospel of Luke.