Doubt it's that expensive. A locker can be made for like $500. But then you're thinking of sheds with a simple lock. If you want something actually safe, you'd need a bike garage, and those can go up to like $4k a piece., or $5k if we're counting cargo bikes.

To install them, you need labour as well. Assuming a $40/hr wage (could arguably be higher, depending on source), and a team of 8 people doing this for 8 hours a day, that's $2,560 a day for labour in total. Two isolate the area, keep the area clean, two drill holes in pavement and breaks up stuff so the boxes can get in there, two transport the materials, and two assemble.

So, assuming 4 boxes a day of $5,000 each, so it's now about $22,560 in total per day (wages included). Let's assume $22,500 here per day. 500 lockers divided by 4 (amount installed per day) then yields 125 days (4 months, 3 days) to install all of them. Thus, that's $2,812,500 in total.

But we'll also need permits. The build plan needs to be assessed for transparency, environment, construction drawings, and the impact for the neighbourhood. It's complicated, but let's say $500 per balcony-like area (a balcony being about as big as one of those 3-bike boxes). So that's $250,000 in total for the permits.

We then end up with a total cost of 3,062,500, or let's call it 3,100,000. Because building often has additional hidden costs and maintenance, I'm assuming 1/3 extra, so it's even better when it turns out to cost less. Then we end up with about $4,000,000, or $0.45 per NYC inhabitant.

Even if wages were $250/hr, it'd end up costing only $36,000 a day total (labour+construction), and thus totals $4,750,000 (including permit). Hidden costs, delays and maintenance included, that's $6,175,000 in total, a fraction of the $25,000,000 that is claimed, with 6 months build time in total (the 2 extra months are part of this 'extra cost' if that happens).

This would mean all of the 500 boxes cost less than a dollar for all NYC inhabitants in total!

That while it gives much more freedom in the form of bicycles. There are no additional fuel costs, yearly checkups, and so on, and you get fitter and stronger, thus reducing your healthcare costs. Bikes literally make you richer.