Nice-to-have widow dressing features like governance or smart contracts built on top of or around a blockchain don’t characterize (supervene upon) its generation. EG, BTC has Rootstock and Rare Pepes trading on Counterparty.
Bitcoin obviously has governance of some form. Just because it’s not centralized doesn’t mean it doesn’t exist in some diverse/diffuse/defensible manner, which increases in capability, resilience, or robustness as a result of stressors, shocks, volatility, noise, mistakes, faults, attacks, or failures.
The generation of a blockchain is defined solely by its security model+protocol.
Gen 1 is Bitcoin’s blockchain, secured by Nakamoto Consensus implemented in sha256^2 proof-of-work.
Gen 3 is Cardano’s Ouroboros, secured by pure proof-of-stake implemented in a provably metastable honest majority.
Gen 2 is everything between Bitcoin and Cardano, including variations of PoW and PoW/PoS hybrids.
(Gen Zero are the scamcoins that cheat by using checkpoints like BAB and Dash, or trusted 3rd parties like Masternodes and EOS’ “block producers”.)