A big NO, for 3 reasons.
1: Although STAB was reduced, it still exists. It is now +20%.
2: Golem actually has marginally higher attack stat than Starmie. Golem 211, Starmie 210.
3: The chance of getting that moveset by RNG is 1/108, which is less than 1%, compared with 1/3 for a double rock move for Golem. Also, you can't change hidden power's type with a TM, but TMing any non-legacy ground move on Golem is guaranteed to give you a rock move.
Double Rock Move Starmie vs Legendary birds
How would a hidden power (rock) and power gem starmie do against the birds compared to Golem? I know starmie has a higher attack stat then golem but no STAB. Would it's dps be higher than a double rock move golem?
Answers
Against a neutral Pokemon like Kingdra with Dragon Breath and Outrage (where Hidden Power's typing doesn't seem to matter), Golem significantly outperforms Starmie with Hidden Power/Power Gem. Too bad, I wish I could use my Double Rock moveset Starmie :( (it's level is too low to be useful out of the gate)
Right now, no.
In future, maybe.
ake Articuno. Golem is going to take 1.4 from any ice move, 1.96 if it gets a water move. On other hand Starmie will take .714
Going from taking Super Effective, to NVE might make up for lacking Stab, and Golems better stats.
I don't know if Pokebattler can account for hidden power typing to trust results from messing around there.