As soon as the big mining companies build their mining farms they will take control of the mining hash power capacity which means individuals wanting to mine will no longer be able to compete. I posted this was going to happen on the forums as soon as the team announced they were going to launch ASIC's for siacoin. There are both advantages and disadvantages, with a big max supply of siacoin it's going to be a race to mine them all that's for sure while selling them off to pay for costs and upgrades, how this will affect host providers profits we don't know yet but this could spell disaster for the project itself without them its all over...
You are missing an important point. No matter how much hashrate is added to the network, the block time, the supply rate and the inflation rate remain exactly the same. The difficulty algorithm changes dynamically to adjust to the current hashrate in the network.
It doesn't matter if the amount of ASICs released are 10,000 or 10 millions or which is its distribution (home miners or a couple of huge farms): the coin supply and the inflation remains the same and can be predicted:
https://www.siastats.info/supply_inflation.html