What's more, most of the manufacturers (from phones to consoles to laptops) don't give a crap about your data and will likely replace your unit with a refurb rather than trying a direct repair. Your game saves? Gone. The photos of your kid? Gone. Your dissertation? Gone. Your accounts? Gone. Most independent repairers will care. Dead IPhone because you got caught in the rain? Your headphone jack broke? The charge connector broke? Apple (or any other manufacturer) don't care and will likely charge you 80%of the purchase price for a refurb with 3 months warranty and unrepaired issues that mean it will fail in 4. However there is a good chance a good independent will be able to either repair the damage directly or at least get you all your data back - even though Apple (or any other manufacturer) make this hard for them by not providing them with the parts and schematics needed. If they had the parts and information recovery would even be more likely.
The manufacturers claim safety issues - for example that if they made batteries available they might explode because someone fitted them wrong. The truth of the matter is anyone willing to do their own repair can already get hold of cheap, usually knockoff or QA failure batteries on the internet to do their repair anyway. If the manufacturers provided genuine batteries then there would be LESS chance of explosion.
Also they make out that the majority of self repairs in electronics would be attempted at home, where in reality most people would not try themselves but take the device to a local independent shop for repair where the staff (mostly - cant account for some idiots in any field, including current authorised repair shops) know what they are doing.