Kiwi rocket company ready to blast off (opens in new tab)

You make a good point. Falcon 9 pretty much launches at will; they go up almost monthly. In that case, it's just a matter of someone coughing up the $80M to schedule a launch. I imagine there is much more lead time necessary to build a Falcon 9 than there is to build an Electron. Dneppr could go up more frequently, since they have a stockpile of about 150 ICBMs to convert into launch vehicles, but for whatever reason, they don't go up more often. Maybe the $30M price tag? PSLV is much more about advancing the Indian space agency's interests than than pure commercialization, so that's why they don't go up more often. But your point still stands, if someone had the cash, they could commission anything to launch--though manufacturing lead time also plays an important part.

Satellites of the size they're proposing to launch (120 kg range) are typically secondary payloads on a launch of a larger satellite; it's the primary payload that gets to select the launch timing and orbit, and the secondary just has to take what's offered.

Unfortunate they provide even less information to calculate the plausibility of claimed payloads and orbits then SpaceX. And we all know that SpaceX changed its specs and claims several times, and that none of those specs provide a plausible rocket, if you recalculate it.

I hope Rocket Lab will do better. I just asked them for the missing specs like empty and loaded mass of each stage, maximum and minimum ISP of each stage, maximum and minimum thrust of each stage, burn time of each stage, inclination of launch site, payload, inclination, apogaeum and perigaeum of or proposed orbits.

Correct, but both SpaceX and Arianespace have rideshares on their large launch vehicles. The Electron is competing with those rideshare opportunities. The current market rate for getting a 1U cubesat to LEO is about $100,000. They will also be competing with NanoRacks.