They are still under the illusion of past glory and it would take them more than two seasons to come back to the Chelsea that everyone knows
Their performance this season means that gamblers should not expect much from Chelsea. I agree with what you said that it will take at least two seasons for Chelsea to rebuild the team into the Chelsea that everyone knows. Maybe even longer than that. I just hope that Chelsea will not become like United where they have been a mid-table team for so long.
We see similar things in many teams this year. The teams that were among the best last year are at the bottom this year, and the teams we know as European giants are currently unable to win matches in their leagues. I don't know why this happened, wrong transfers and the departure of good players from the team may have been effective in this
Basically, the competition in the Premier League from season to season is becoming more difficult, especially if Chelsea still needs time to adapt and or to build chemistry. Then of course, this factor will make Chelsea slow to develop during the increasingly difficult competition in the Premier League. Because we know, that Chelsea will always choose a quick decision to fire the coach, so it also certainly has a bad impact on the development for the team itself. Therefore, it seems no wonder that at this moment Chelsea is still difficult to rise, because they still do not have a good foundation as a team with many new players in the squad.