Why did the Corinthian church have developed excesses by the time Paul wrote 1 Corinthians?
The Corinthian church had operated long enough for teachings to evolve, allowing men's ideas and innovations to enter. What began as Paul's original instruction drifted from one position to another, worsening rather than improving. Their attempt to make the Lord's Supper a full meal illustrates this drift, producing excesses Paul had to correct.
Les explains that by the time Paul writes 1 Corinthians, the Corinthian church had been operating long enough to build these excesses. They had been going long enough that "kooky ideas" were coming in. This was not what Paul taught them at the beginning; it was an evolutionary thing, moving from one position to another and getting worse instead of better. Men can connive and come up with the craziest ideas, and sometimes it is good, but it leads to excesses. At Corinth, when they got ready for the Lord's Table, they realized a little cup or swallow of wine and one little piece of unleavened bread could not satisfy a whole day's energy, so they began bringing food to make a real supper. That led to excesses, so Paul had to bring criticism and remind them of what the Lord revealed to him about the Lord's Supper.