To be fair to Epic, they did succeed in providing competition to Valve on the developer side. Steam's different tiers of revenue cuts was very likely a direct result of EGS existing. Epic Online Services provides a better offering than Valve's. To be fair to Epic again, I don't know how you would hope to compete against an entrenched market leader with 20 years of head start, a carefully crafted "good guy" image, high levels of customer satisfaction and no sign of complacency. It's just that their plan was so godawful that it was doomed from the start.
If they felt they had to play the role of the villain against Steam and try to force themselves into the market, they should have done so at Microsoft's "I bought the bank" level. They should have moneyhatted every medium to major release for at least three years, but that would have meant burning through their Fortnite cash at an extraorrdinary rate. Instead they half-assed it in every way and now whatever small amount of momentum they had managed to pick up is dead in the water.