Two servers with 64GB RAM each and a few TB of storage can easily run a thousand full BTC nodes. This isn't a big expense, ...
If SPR node ops can run a thousand BTC nodes for a few $ a month each, so could BTC zealots,...
I tried installing as many daemons as possible on a 24 GB RAM server a few months ago.
I was only able to start about 15-20 of them before running out of RAM.
(And most of those daemons were for small altcoins that didn't have the high verification needs of BTC (lots of CPU, often up to 100% during synching))
1000 daemons on 2 servers is not possible, you need to spread this over a few dozen servers, plus it will probably cost you a few thousand dollars a month.
Also, with SPR we will have the requirement that every node needs to run on a unique IP.
So having enough servers to be able to run 1000 daemons is one thing, but having unique IPs for every single daemon will cost you a fortune. Every month.