Yes, it's expensive. But you have to compare it fairly: think of the cost of racking up servers w/PCI FPGA cards or devboards with FPGAs and JTAG flashing tools. How many of your team can you enable with these solutions, and how long will it take to set it up? What if you're a small team working on a RISC-V compiler and you don't have an IT dept?
If you've got a global team, then it's even more interesting to reproduce these configurations reliably among multiple sites.
Also, if you have to need 10000 for a day to do some sort of dev/QA/integration efforts you don't have to actually own them. Or even physically deal with the things.
The 'VU9P has ~2.5M logic elements and 6840 DSP units.
The M2S090 has ~90K logic elements and 84 math blocks.
It's nowhere near the same class of device.
The AWS FPGA offering only makes sense if you absolutely need a massive FPGA connected to massive amounts of RAM, and don't want to spend the bucks to own it yourself.
If you've got a global team, then it's even more interesting to reproduce these configurations reliably among multiple sites.