Of course having the plans is great. I wish all information was free. My point is that planned obsolescence, assuming it exists (which I do) can only be solved by the manufacturer. Even if we make an open source blueprint for a given appliance, It will not stop the manufacturer from modifying the blueprint by using cheaper materials or otherwise ensuring that the device breaks in x years. The only relevance open source blueprints has that I can see to planned obsolescence is that is lowers the barrier of entry to making a product, thereby increasing competition and somehow making it easier to make quality products. I can't save for sure, but I would assume the largest barrier is building and scaling the factory, not the blueprints. The manufacturer ultimately has the last say here.
One solution is the hire a factory to build the product to spec. Here we can deal with planned obsolescence by raising consumer awareness about a given blueprint, so that they know to buy the right spec. That sounds a lot like HDMI, which has no shortage of low quality implementations. now that's not a perfect comparison because HDMI is only one part of the cable and I don't know how much needs to be verified to qualify but ignoring that there is another issue of simply uncertified products altogether taking advantage of the name to sell worse quality products. And this leads me to my last point which is that it may not be feasible to have a standard like HDMI for appliances like a blender. The reason HDMI exists at all is not because of quality per se but because devices need to work together. So what results of this in my opinion is that there are a lot of (too many?) prerequisites to solving planned obsolescence, definitely more than just publishing the plans.
If parts and designs are standardized, if your particular manufacturer has skimped on a part, you could replace just that part with an identically specced one from another manufacturer.
edit: And I don't mean that everyone uses the same type of clothes iron, I mean that the type of clothes iron you use isn't tied to a particular manufacturer.
The idea is for the design to be repairable and the plans available. These can specify materials as well as shapes etc. Basically, if it needs to be specified to meet a level of performance, it can be so specified.
In terms of mass sales, yes a manufacturer would have to make it. But multiple manufacturers could and they may not "cheap out for obsolescence sake" in the same way. And if they do, a person has the option to make it themselves - whether or not it makes economic sense.
This is still better than the current situation where the customer has to pay money, cross fingers and hope.
One solution is the hire a factory to build the product to spec. Here we can deal with planned obsolescence by raising consumer awareness about a given blueprint, so that they know to buy the right spec. That sounds a lot like HDMI, which has no shortage of low quality implementations. now that's not a perfect comparison because HDMI is only one part of the cable and I don't know how much needs to be verified to qualify but ignoring that there is another issue of simply uncertified products altogether taking advantage of the name to sell worse quality products. And this leads me to my last point which is that it may not be feasible to have a standard like HDMI for appliances like a blender. The reason HDMI exists at all is not because of quality per se but because devices need to work together. So what results of this in my opinion is that there are a lot of (too many?) prerequisites to solving planned obsolescence, definitely more than just publishing the plans.