Huh, I'm less doubtful of this than I thought I'd be. Tower cranes are apparently surprisingly low-maintenance. I assume this is because they have to actively participate in their own disassembly [1] and major breakages are super difficult to deal with because they're at altitude, so they need to operate reliably enough that they can always take themselves down at the end of a job or if they need a major repair (cracks found in main pivot ring, etc). Concretely (pun not intended), I found a document [2] saying that 10 tradesmen and $35k/month in parts (together a bit more than $1m/year) can keep a fleet of 70 tower cranes (15 metric ton lift capacity each) at ~80% utilization over a one-year period. So, yeah, I'd definitely believe that you could run these things at the quoted price.
1: https://www.youtube.com/watch?v=Nww6MN_Lxeo&t=24s
2: Annex 9, "Example of the Use of Key Performance Indicators for Maintenance", in this PDF: https://www.mantiscranes.ie/wp-content/uploads/2017/01/CPA-T...