Here's the problem with ECW. To establish a new promotion, you have to be willing to take a loss. Yes, Eastern Championship Wrestling existed in 1993 out of the ashes of Joel Goodhart's Tri-State promotion, but it was very limited in scale. After Gilbert left ECW, Heyman took over the booking and began using it as a testbed for concepts that he wanted to employ in the World Wrestling Network promotion in late 1993. That never got beyond an unaired TV pilot (recorded in HD!), but he found that his ideas in the meantime were being well received by the Eastern Championship Wrestling audience. The promotion began to grow, and grow fairly quickly. However Heyman never an outside investor (apart from Tod Gordon and his parents) to bankroll any expansion to the territory. In that, the wrestlers became the investors (wittingly or not). ECW incurred debt the more it expanded, and never was able to get out of that hole.
It's not that the territory was not profitable. Their biggest attendance came in 2000, when they drew over 5,000 fans for a PPV. They arguably could have drawn considerably more, but there was great financial outlay involved in booking a basketball-sized arena. The PPVs also put them in a hole. Not that they weren't profitable, but consider this. From what I recall, the outlay for doing the Barely Legal PPV was something akin to $1M. They certainly did not make that up in the gate, as it was held at the ECW Arena which could only hold 1,000 fans. The PPV had a decent buyrate, but revenue from the PPV purchases took months to hit the company coffers. In the meantime, they had to do the next outlay for the next PPV, and again wait for months afterwards to gain the revenue for that show (held in the small War Memorial Coliseum in Ft Lauderdale - I was there). They could just not get ahead.
Heyman really needed a really rich investor like a Rick Rubin, Tony Khan, or Robert W Carter to put enough money into the promotion so that they could expand properly, book the larger venues that they could have filled relatively easily, and get over that initial PPV hurdle.