Turn 1 - workshop, sol ring sphere, sphere. Turn 2 - any land into fleetwheel cruiser. It cost 6 mana sure, but its done on turn 2 with 2 land drops.
You can't cast two spheres with just Workshop and Sol Ring.
Workshop, tap +3
Cast Sol Ring -1 = 2
Tap Sol Ring +2 = 4
Cast Sphere/Thorn -2 = 2
Cast Thor- no it costs 3 now.
If you are going Shop, Mox, Sol Ring, Sphere, Sphere, Cruiser - what threats does that leave you with when the automobile is uncrewed? And if they have Misstep, Force, or MBT?
What you are describing is also possible with a few decks, not just with Spheres, even if less consistently. I mean i don't disagree, the deck is powerful, but you can't have Sol Ring or Crypt every opener.
The moment Wizards prints artifact removal that circumvents tax effects, Shops becomes a manageable card (and by extension archetype) again. Cycling, Channel or a new keyword is all it takes. One new green or red card and we're fine again.
These cards already exist. Steel sabotage is a card. So is Ancient Grudge. Spell Pierce Hurkyl's Recall By Force etc. etc. This is without getting into the hosers that you can play if you run an actual manabase instead of a greedy pile.
Have to agree with cutlex here. What would be gained by a cycler? As awesome as that sounds, seriously, what would be the cost a nearly-uncounterable artifact-destruction cantrip? Most likely 4 mana, honestly. You've got Slice in Twain and even though it's an uncommon, printing a better version that has some kind of primary effect with this as backup but with nearly uncounterable? I don't see this happening. And 4 mana is not where you want to be. If it were 3 mana, how does that compare to casting Grudge at 3-4 mana, or Ingot Chewer which still costs 3 when there are 2 Spheres (not Thorns) down? @ChubbyRain is also right though, that 1-for-1 removal is not really where you want to be either, but some of us are not playing Tinker and Colossus.