This is normal and comes from the old times. There was also hard to adjust the old "dumb" phones and most people still don't need to "tune" their phone. Of course you can get more from the phone by adjusting the phone system and internal data, but you can also brick the phone by doing this. Manufacturers hold the warranty, test the updates and are therefore sure, the phone will work as promised. Of course sometimes telco also cripples the phone (for example by locking extra RAM, so phones with the same specification but unlocked RAM can be then sold for higher prices, or disabling hotspot features), but mostly they just install harmless apps (MP3 shop, newsreader, not-changeable homepage in webbrowser, ...), but this has nothing to to with phone manufacturer, this action are done solely by carriers. It's not a big problem in Europe, because the phones are sold unlocked to any carrier and if you don't like the "adjustments" made by one telco, you can buy the phone from any other company or unbranded.
The only big unfair thing is, if carrier don't allow to make updates for their branded phone, even if it's available for other carriers and unbranded phones, but this is, again, carrier's responsibility. There's always option to end the contract and find another one.