Then you aren't managing your MP Well enough. Beckoner's Hands and Feet Teamed with /SCH storm spells would more than enough cover the Prep Cost for swapping in Helios armor pieces, that's also counting Auto Refresh and If you Took the Time to get the Evoker's Ring, which has been a staple for SMN since ever. You can also get an Icarus Wing and unlock Myrkr and Restore MP that way. Not to mention the Emp. Reforges still have a Blood Boon Bonus on them, that helps with your MP cost. Yet another Job Trait bonus that's useful to a pet job.
So much like the Brave's Warbonnet or The Stout Bonnet that gives Reward Recast Minus (Oh and Charm Vs. Beast +6 Because Charm is used oh so much now in things)
Except with the proper distance, you're not going to die. I spent most of my time leveling SMN in Ifrit's Cauldron and you learned that you picked on Bombs, ran away and continued this until it used Self-Destruct. If you did The Trial-Size Avatar battles, that's how you won, by sending your lovely little Radioactive Squirrel to its doom a crap ton of times while you went to the entrance and back to the top each time you summoned, all the while using items to keep your MP in the Positive. That's before Elemental Siphon was a thing, and that the Elementals weren't next to free, and you had a crap ton of options for -Prep. And as a SMN, you're not getting near that stuff, because now you have a great distance range for your abilities and you're Backline job, so you can get away with dismissing and resummoning in a party, because you're not going to be in the AoE that cause weakness or that causes Terminal DMG and your avatar takes a few seconds to replay, where BST takes 5m and 20m to replace, each one costing money because those pets are also consumable.
There's a major difference, The Nirvana drops your level by 2, Unequipping an Ilvl Axe drops BST's Pet lvl by 20, and you can get away without the Nirvana. Not to mention that no matter the case, BST pets can't go beyond 119, unlike your Avatar which can go to 121/122 for Carbuncle and Cait Sith.
That's been the only correct thing you've said thus far, but SMN is still in better shape than BST.