Its a bit of a hypothetical to be honest. While I agree focusing on grabbing the oil fields was probably the better strategy (in hindsight)...Hitler (plus a number of his generals who he unfortunately formed an echo chamber of) had a strong and valid reason for going after Stalingrad past just the name it bore (which has been overhyped by many historians I feel).
This was to guard the rear (and logistics chain) of the caucasus assault...a break (both bank control) of the volga river was needed at some point to accomplish this (given the supply route of the river +Caspian Sea for the Soviet forces to assault any weakness in the Caucasus supply chains both before and hypothetically afterwards too).
The mistake was in choosing an urban environment for this break (the name of Stalin in the city did tip this for Hitler)....but again its easy to see it in hindsight. At the time of the initial assault on Stalingrad, no one had any idea what sustained urban warfare would be like (it wasnt even really planned for by the Germans, they expected to conduct swift encirclement). Even Leningrad (closest parallel at the time) was effectively a partial siege. But the idea to take no chances in protecting the rear of the caucasus assault comes from sound strategy too (given the Germans had faced such problems in various theatres of barbarossa earlier). It was implemented badly (and with bias - a commanders worst enemy). In hindsight, a breach of the volga river could have been done at several other areas without a city to slow it down and act as an eventual quagmire and turning point.
By the time it had turned to a morass and logjam, Hitler valued saving face over sound strategic doctrine...and the rest they say is history.
@AUSTERLITZ @Levina @The Sandman @Desert Fox @Psychic @Vergennes@vostok
Your inputs if you have any regarding this?