It's a genuine concern, and the honest answer is "sometimes, which is why you shop around." The worry is the classic subsidy dynamic: wherever a grant or a tax break exists, there's a temptation for prices to drift up to absorb it, so the customer doesn't see the full benefit. It's arguable that the 0% VAT in particular became margin for installers in places rather than a clean price cut, and that hardware should carry only a modest markup over wholesale but often doesn't.
The proposed fixes people float — like SEAI setting approved cost ranges for each component, or zero-interest loans instead of grants so repayments come from the bill savings — reflect that frustration. Those aren't the system we have, though. What you can do today is treat the grant as *your* saving, not the installer's, and verify it. Use the rough per-kWp guide (≈€1k/kWp, ≈€550 for an Eddi, ≈€1k per 2 kW of battery, after grant) as a yardstick, get three like-for-like quotes, and be suspicious of any "rewards scheme" or padded extras that conveniently equal the grant amount.
The market is competitive enough that good installers do pass the savings on — the after-grant price for a basic 4 kWp system from reputable companies sits around €5k. If a quote seems to have quietly inflated to swallow the grant, comparing it spec-for-spec against others usually exposes it. The grant and VAT relief are real savings; making sure they land in your pocket rather than the installer's is just a matter of doing the comparison.