It's not that they conflict, but that looking at the history there is a clear development of theology often drawing more on pagan philosophers and practical concerns than any indication of an apostolic succession of bishops. Ultimately, the transmission of the church is a matter of faith but it seems to me there is too much history that's necessary to deny to uphold the notion of an unbroken church transmission outside of the Scripture itself. I'm not sure what specific statements you're refering to in the Didache, though my statement is simply that there was a development of sacramental theology and it's been my experience that generally the things people see in the early documents tends to be a reading later developments into texts rather than them actually being present. Though I will say I'm not really interested in debating the issue because there is more faith in believing the EO is the true church than analysis, so I am simply stating my conclusions from reading the early church literature and outside historical sources.