Can someone explain this?How is it possible for WTI to go to...

Can someone explain this?

How is it possible for WTI to go to negative 30 odd with Brent approx. 25 where theoretically if your a buyer why not take the negative 30 instead of paying 25 in terms of market options?

Now some might say if you take the negative 30 you have to have a ship somewhere to pick it up immediately so its not realistic and generally pragmatic. If thats the case why has the WTI reference not automatically shifted to at a later timeframe with the immediate period reported as a secondary guide so a later price, reflective of pragmatics and genuine demand and supply fundamentals, can be singled for comparison to Brent?