The biggest problem with going for something like CSM or Storeroom is that the other player is going to adapt to what you're doing. Sometimes, that will mean contesting you on Gardens. If you rush your enabler, they'll just build their economy out, then contest you a little on Gardens at the end, probably picking up a couple. Alternatively - and probably more common - they will just go 'over the top'. You're getting Gardens? That's cute, I'll get every province in the supply. The key adaptation here is that they don't waste their time going for things like duchies, preferring to build their economy up more. You, the Gardens player, need a way to end the game. So you can get 8 Gardens. Sure. And you can get 40 cards in your deck, I believe you. But how are you ending the game? You may be ahead on turn 14, but the game is not about that - it's about ending the game whilst ahead. This is the great advantage Ironworks has - it gets to both establishing your matrix of Gardens and cards quickly, and then being able to slam the door shut afterwards. Cards like CSM and especially Storeroom lack this closing power. Let's say you're playing Storeroom/Gardens, and I completely ignore what you're doing. It's going to take you at the very least 22 turns, and probably 23-24, to actually end the game. You can get 5 point Gardens in that timespan, plus all the estates. Sure. I just need to get all the Provinces by then, which is not too terribly hard for a BM deck focusing on that. But it's actually even worse than that - in order to achieve your turn 23-24 result, you need to empty the Storerooms ASAP, then move to Gardens, then finally Estates (actually you could go for Estates before at least some Gardens, and possibly should in this not-realistic-simulation-world - you are going to run into too many hands without Storerooms after very long, and that's going to cost you a few turns). But if you wait so long, then Big Money player can actually snipe Gardens from you towards the end, which on one hand speeds you up, but on the other actually has more impact for them than a Province in terms of swing (minus five for you, plus three for them in a lot of cases). They don't want to do that until late, because it hurts their deck more, plus it's helping you end the game. But late enough - let's say, stealing two - and they're going to have very nice chances indeed. So you can move to pick up your Gardens sooner, to try to combat that, but now you have fewer Storerooms going in, which is going to make your deck grind to a halt more easily/often, which means you're oozing a few more turns, so they can ignore you now and just head straight for Provinces.
The key is adaptability, and the problem you have as the Gardens "rush" player is that they have much more of it than you do. Now, why do they? Well, basically because their deck is economically better, and this lets them split for more different kinds of victory points at whatever time they want, and be better-equipped to do more things afterwards. They also have access to a source of VP which is just worth more than you. Plus you don't really have a good plan to end the game on your own terms, which gives them a lot of flexibility.
And this is all talking about Big Money - engines are going to generally do all these things even better; Engines are a bit slower, but you are playing a really slow game, which allows them a lot of time to do anything they want.
The issue is, these things aren't really rushes, because you don't really have a way to make sure the game ends against an unpanicking, uncooperative opponent (and good players will have both of these characteristics, even if simulators do not). So you're really not playing a rush so much as you are a slog. Slogs can work, but they need to be able to have access to large amounts of VP that it's really hard for other decks to get to. Duke works really well for that because they're worth nothing if you don't prep by getting duchies first. Gardens CAN work for that, but you really need to be able to get lots and lots of cards and/or be able to get lots of Gardens AND lots of duchies relatively quickly. Silk Road, very similar thing, generally. There are nuances of course, but hey, I've written a lot already. Anyway, this is why Beggar/Gardens is really strong. Only a few Beggars gets to the Gardens pretty quickly, you get massive amounts of copper (so lots of points), and you don't have tons of problems reaching into duchies. But it's more a slog than a rush.
CSM is a little trickier, I haven't tested it, maybe you can rush a bit. I'm not totally sure. But I have a feeling you're going to run into some of the same problems as Storeroom, though maybe not quite as bad. You do have the added issue that you're buying a bunch of coppers-with-buys, though, and that is just not a really strong card. In any case, I would guess that the Jack deck wants one CSM in it, at least if you know/once you figure out they're going for mass CSM/Gardens. Possibly just in general.
(Edit to fix a typo).