This statement is false. Blocks will continue to be produced on average every 10 minutes with or without pools.
With 100,000 people who have equal hashing power, they will produce a block on average once every 2 years.
With 144 mining conglomerates they would each produce a block once per day.... of course, if you increase mining frequency to once per minute, then you could have 1440 conglomerates each producing on average once per day.
The end result is that hash power would end up held by a couple thousand conglomerates each of which would still have acceptable variance.
Anyone with 0.05% or more of total hash power could produce daily. Anyone with .001% of the hash power could produce monthly.
How many total individual miners does Bitcoin have today? There are only ~500,000 unspent outputs. If 1% of all bitcoiners have mining hardware, that would be 5000 people mining.
How many individuals miners actively mining less than 0.08 BTC per month? Those are the only individuals who might get excluded by solo mining.