| Incorrect. 1. The number of nodes is not fixed. 2. The process for node selection is random, based on the amount staked. This happens continuously. 3. The D in DPoS is entirely optional. Anyone holding Tezos can directly participate by running a node. The only cost is the cost of a VPS. The only real restriction* is a 10000 XTZ minimum for running a node. At current / ICO prices that's around $5k. While that's not cheap it's a lot more attractive than the CAPEX/OPEX of mining hardware. Also, that $5k will grow by 5.5%++ per year, i.e., no depreciation of hardware and only a trivial amount of overhead. Those not wanting to run a node (or with less than 10k XTZ) can delegate to a baker. There are a wealth of them available already. *This restriction may be lowered in the future -- by way of on-chain voting (as opposed to a hard fork). |
Some numbers regarding decentralisation: The last couple of (3-day) cycles the number of unique blockproducing nodes (bakers) has averaged just above 200 pr cycle, and is steadily increasing. The Tezos foundation nodes are now down to producing ~25% of the blocks.
I recommend this post for anyone interested in Tezos 'Liquid Proof of Stake'-model: https://medium.com/tezos/liquid-proof-of-stake-aec2f7ef1da7