I said they haven't had anyone as talented as Foden to bring through, so the "less talented" players benefitted from the loan system. Which is what he said.
The closest they have is Hudson-Odoi, who has not gone out on loan.
Mount, Tomori, Abraham, James and Christensen all went out on loan, none as talented as Foden, and half will be gone in a year.
This also ignores the hundreds of failed Chelsea loanees (Baker, Loftus-Cheek, Miazga, Piazon, Sinclair, Kakuta, Dasilva, Kenedy, Chalobah, Grant, Nathan, Nartey, Maddox, Brown, Cork, Solanke, Colkett, McEachran, Scott, Kalas, Aina, Boga, Mellis, Musonda) and the fact Chelsea would never have given some of these players any chances if it wasn't for their transfer ban.
If Chelsea had someone as good as Foden then they would be able to bring them through without any loans.
They tried with Hudson-Odoi but he's not as good as Foden.