If we had a closed-source project then this would be accurate, but we don't. It's an open system and any developer can add any "magic limits" they choose. However, developers can only provide the code. If users don't agree with those magic limits, they won't run that code. The evolution of the network is decided by the code people freely choose to run.
Some people tend to compare competing codebases to a vote for governance, loosely akin to democracy (or dictatorship, depending on who you listen to ). But I've never been fond of this comparison. It's far cleaner to see competing codebases as products fighting for market share. Developers design their product however they like, with whatever magic numbers they like, in an attempt to provide the superior product. The market then selects via consensus. If there's a resulting gap in the market, where users aren't happy with the code, or the magic limits contained therein, it's only natural that competition in the market will provide some alternative code for users to run.
That means the thread title can't be correct. We're not trusting "someone", we're trusting the *market*. If SegWit doesn't deliver on its potential, the market could well react to that and select a change to the codebase. If there is ever an imbalance in the alignment of incentives, it certainly won't stay that way for long. Embrace the chaos, as it were.
Development centralisation is concerning to many. Everyone seems to doubt the motives of everyone else. People fear "takeovers" on both sides. It's easy to get bogged down in all that negativity and it's easier still to start casting aspersions on those you see as a hazard to the well-being of the ecosystem. But the whole thing gets a lot less scary when you remember that the code can't lie. Neutral and transparent wins every time and that's what Bitcoin is. Whatever you think about the developers, their intent or their proposals, trust the market to choose the best code available at the time.
what devs need to do is have all variables changeable within the compiled GUI/command prompt.
EG not just the transaction fee defaults.. but other things too
USERS should have the options. like the blocklimit should be an option a user can change within the compiled release of all different implementations.
the problem is not that one dev team should be trusted more then another.. its that even if you only trust one dev team. the users should have some self control of what the rules should be.
EG not rely on electing a team based on a fixed pledge that once elected you dont have any ability to hold them to their pledge for a few years.. instead. the user gets to dictate the rules whereby the team have provided them the open platform to vote on each rule.
EG at the moment its more of a 'go for trump if you want separate minorities(witness)'. or go for Hillary if you dont want walls(no 1mb limit),
where each side is a overall pledge of many laws.
rather then an open system where each law is votable,
where all you are electing a team for is to have the best team that will follow the independent consensus decision best.
not electing which team who decides which consensus should be best or should be ignored.