In reality two "electricity pumps" are connected to one 135kW charger, so if you're charging next to another car, you get about half the power. The rule is that the first car to start charging gets the most power and the second car gets the leftovers.
Recently Tesla owners found out about new charging rule, which wasn't publicly mentioned before. It's about the car's battery management system, which limits the maximum charging speed, in order to protect your battery, if you're doing a lot of fast charging.
Bjorn Nyland was one of the first owner, who noticed the limitation, as he goes on long trips almost every weekend in his Model X P90DL and rarely uses slow charging. When he got the car, he could supercharge at around 115kW max, but now, after just a few months, he can barely reach 85-90kW max.
This is an interesting problem, as there are real physical/chemical limits to what Li-ion cells can do, so one simple solution is to lower the charging speed, BUT going into the (near) future there's at least one other solution: putting the same amount of charge into more cells, so each individual cell gets charged slower.
Today Tesla's biggest battery pack holds 100kWh of power and in theory all Tesla batteries could be swapped out with these large capacity ones, in order to improve range and charging speed. The owner would have to pay a significant, but affordable fee.
In the long term this is a real problem and needs to be fixed somehow, because fast charging is very important for long distance travel, city taxis and other logistics, where time is money. Tesla promised owners faster and faster supercharging, NOT slower and slower ...
Read more about the subject on Electrek.co.