Let's employ critical thinking outside of the box of Westernized Christianity?
Consider this perspective:
Jesus' way of discipleship looks nothing like how it is done today.
In today's terminology, what Jesus did with his students was evangelism. It was a 3-year process of introducing them to Kingdom truths. Other excited unbelievers joined up, but many turned back when he began to say some hard things. When they were committed enough He sent them in pairs into citites, even able to use His name to heal the sick, cast out devils.
He promised after he was gone that they would do greater works than He did.
They did not technically become true disciples, or complete their discipleship program, until they were baptised with Fire and the Spirit (predicted by John the Baptist, and did NOT happen in secret in a hidden "upper room", but publicly in The House (aka: The Temple)), after His resurrection.
His commandment in Matthew 28 is how we are to do what He did:
1. make disciples of all ethnic groups
2. Baptize them
3. Teach them to replicate
However, Because the Lord goes before us, the disciple all enthic groups phase can be very short due to His appearing and angelic appearances to unbelievers ahead of us.