Based on my experience with the deck, Jeskai and other Xerox decks can be built to beat any deck in the format consistently. What they cannot be built to beat is every in the format (including the mirror).
If the goal is to beat exclusively Jeskai, your strategy should be to align your threats to match up effectively against their answers. For instance, the Jeskai variant with Lightning Bolts, Fiery Confluence, and Snapcaster Mage was built for a Combo, Oath, Control, and Shops heavy metagame. The maindeck burn is never dead as you can use it to close out games, but it matches up poorly against Dredge's SB strategy of Fish Zombies and decks that run 4 toughness, non-artifact creatures (i.e. Eldrazi) or creatures immune to removal (i.e. TNN outta Merfolk). That changes if the deck skews towards White removal and Pyromancers as those are much more effective at combating creatures, but you end up with sub-optimal cards against Oath and Combo, along with a much weaker SB plan against Shops.
Basically, Shops and Survival (to a lesser extent) are strategically favored against the Jeskai Strategy. Fast Clock+Spehre Effects+Minimal vulnerability to Mental Misstep/Pyroblast are the keys to beating Jeskai, and they make a high percentage of Jeskai cards irrelevant ("Treasure Cruise!" leads to "you're dead" fairly often in those matchups!). Everything else, it's hoping they have to cast a few cantrips to get to where they need, and that you can kill them in that window.