The genesis block contained 50 BTC like all other blocks in the first 210,000. This can be verified by any full node with a copy of the blockchain.
https://blockchain.info/block/000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f
Due to an early client bug the coins in the genesis block are unspendable and it is highly likely that will never be "patched". Doing so would make new clients incompatible with older clients and would cause a hard fork.
In the first year Satoshi probably mined a large number of coins however the network and source code was publicly available at that time, it just happened that very few people could even be bothered to download and run the client. The newslis, where Satoshi published his whitepaper and a year later the first version of the client (pre bitcointak), had more than 10,000 subscribers yet it would appear less than a dozen even downloaded the client. Kinda hard to believe now but the early launch of Bitcoin was rather lackluster.