That seems excessive, but if you have a big house, even decent blinds can add up. When we built our house, we designed it with essentially two windows for every "window". For example, in the bedrooms, there is one fixed pane and one operable pane that opens like a door with a crank handle. Guess what! Two blinds needed instead of one! Brilliant design, thank you. We haven't put blinds in every window in house, but we have put blinds in something like 9 sets of windows with 22 total blinds. It cost us $7,000 over about 5 years. Fortunately the way the house is designed, only 4 of those blinds block views into the house from off of our lot.
$40,000 is an unfortunate number (so is $7,000), but it reflects more than just decisions on blinds - it's house and size and design decisions also.