and use it to attack, disrupt or snoop in on Monero's network in its intensified fight against darknet markets ?
Security-wise the low number of full nodes and its direct connection to darknet markets is making Monero very vulnerable.
Even with 2000 full nodes, the situation does not really change .. this will still be a weakness for Monero as its direct connection to darknet markets is
putting a bullseye on Monero.
With regards to blockchain size i think in a few years when the blockchain has grown considerably, Monero will face the same problems that Bitcoin is facing currently,
by not rewarding people to run full nodes its full nodes network will deminish over time.
No it will not. .
Monero has an adaptive blocksize limit that avoids the whole Bitcoin blocksize debate. This adaptive blocksize limit works because Monero has a minimum block reward of 0.6 XMR per block in perpetuity. This means that there is no need to rely on transaction fees to secure the proof of work (miners) as is the case not only in Bitcoin but in coins such as Dash that have a fixed maximum number of coins. In the case of Dash the problem is magnified since the falling block reward has to support not only the proof of work but also the masternode network and the funding of projects.
Once the fees are no longer required to support the proof of work etc., they can actually be used to create a market for scaling the blocksize. One significant advantage of this is that it avoids the kind of spam attacks against the memory pool that were recently launched against Bitcoin. These attacks rely on the fact that the bulk of the spam will never be mined because of the fixed blcoksize effectively having a minimal cost to the spammer. As someone who runs full Bitcoin nodes I am well aware of the bandwith costs of these spam attacks.
Bitcoin's problems, or Dash's problems for that matter, with scaling cannot be solved with a continuation of Moore Law, Nielsen's Law etc. alone, because of the falling block reward approaching towards zero over time.