Even for a large off grid whole home PV system that can operate through December/January at high latitudes.
Let's say for an example you wanted to DIY a PV system that would be much too large to fit on the roof of a normal sized house.
Go calculate the cost of buying 30000 kW of good quality 72-cell PV panels rated at 380W STC each. It'll be something like 80 pieces at about $130 per piece.
Usually would ship as 20 panels per pallet, so call it four fully loaded pallets of 72-cell panels.
At 34 cents/W STC rating, PV panel cost from distributor something like $10,400 to $12000 USD.
The foundation work and poles/racking to do a basic ground mount will be a huge cost on top of that. Labor is a big part of it. If you're hiring people to build it the labor and ground mount gear and things like basic foundation work/screw piles/steel tubes set into concrete could easily cost you another 10 grand from a local contractor.
Something generally along these lines or an industry competitor of it:
https://www.ironridge.com/ground-based/
(Not discussing inverters/charge controllers/batteries/disconnect boxes and wiring here).