The government is taking action. The government is in on this consolidation via investments, contracts, preferential legal & tax treatment, etc. Think about this from the government's perspective. The government would rather govern a small number of large entities instead of a large number of small entities, thus the government is incentivized to favor monopolies/oliogopolies. The government itself is a monopoly of power in many domains.
Sure, the government may intervene with a company getting too big, but the intervention is so the government can gain a foothold with that company. e.g. any telecommunications platform will need to have back doors for the law enforcement agencies or said telecommunications platform will not be allowed to operate.