I'm sure you can accumulate EV. If you buy my free play you've accumulated EV. If you say to me "Alan give me $300 to lay the number 6 on the ALL bet because that's the only number I need and I'll pay you $400 win or lose" that's accumulating EV.

But I have a hard time saying "I just lost $8800 but it's the best day I ever had for EV" or "I just lost $8800 but that was additional positive EV for me."

EV is expected value, before a bet is resolved... unless you're telling me the definition has changed.