Who holds more power, the public or the ruling power?
There isn't even a show that the public holds any sort of power. It's known by now that the Five Families hold the power in the world and until the Five Families die off, that's not going to change. The five families are as follows:
Vaitash'ehl - they were the doctors, the ones that ran a top pharmaceutical company that made the virus that nearly eradicated the world. They aren't in high standing at this time, not even with the Tech-God on their rooster.
Fenyx - Soldiers. Military. Mercenaries. The Fenyx family trained the world's militia (different from each sphere's military) and were used in case of an attack against the planet (or, as it was later seen, these mercenaries, at Tarren's urging, defected and fought with the Tenebrae). The Fenyx Militia (or the Fox Calamity as it's now called) are known to be mercenaries that will fight for whomever will pay them the most, with little exception. Currently, the Five Families have them in contract.
Grey - The technological group that kept their finger on the pulse of the world. They were the ones that made sure that they were always a step ahead of the competition, all competition, even others in the Families. Daniel Grey was the first ALTER to be created, and now, the lottery gives one 'winning' family the chance to change their child into a Synth, a modified, genetically 'perfected' transhumanist.
Ducalle - they were the ones responsible for the temples. They kept the god days and sacred numbers. They were the first family to be brought to the brink of extinction in the private war that they had with the Greys.
"The Fifth Family" - These were your smooth talking politicians/ba, these were the ones that bartered deals between the other families and were the 'mediators' (even though they were known to cause trouble if it benefited them.) This family was nominated every nine years by the people (even though the Four Families oversaw the election). There was some talk once that one of the elected families would finally become the established 'fifth' but Alcion's assassination changed that.
The Tenebrae is the only balancing force to the Five Families and this group came about as a direct answer to the Vaitash'ehl Crime Family, and at first, targeted only the Vaitash'ehls but later took their war to the Five Families as a whole, yet, the Tenebrae need the Five Families. The Tenebrae are infiltrators, they gain information, they keep everything in check, and the Five Families understand their slippery position. If one unified power were to rise (as it nearly did with Alcion), the world would have to shift and change, and during an age of space exploration and rapid technological advancement, the Tenebrae make sure that things remain stable, at least for now.
The people understand this, they may not like it (due to the extreme disparity between the Five Families and everyone else) but they know their place. They remember stories of the Tenebrae Revolution. They know better than to challenge the government. There are moments when a riot happens, but the Fox Calamity step out quickly and put it down. The people, for the most part, are happy (and by happy, one means sated) they are kept content with technology, healthcare, and entertainment, and the Five Families never let anyone see what is going on behind the curtain.