He is right, there isn't enough money in top level English rugby. Derek could never have provided the amount needed, nor the Worcester owners, and neither can the owners of maybe another 6 premiership clubs.
The Legends and whoever is taking on Worcester will not be able to fund their teams at Premiership level. They might even struggle at Championship level, what with the P share gone, no TV money, and very little funding from the RFU.
If those other remaining clubs who do not have enough money do not find a sugar daddy (and I doubt that they will), we are simply going to witness a very slow and painful decline.
Attendance money is simply never going to match the salary needs of a top club. Even if you had a stadium totally free of debt, there is a shortfall of many millions every year.