This is my first post on this forum so take it easy and understand me.
I am 38 years old player who has played many different games during those past 20 years.
But those last few years, games have become more and more unfinished products with lots of problems.
I'd agree. It's the demands of the industry, sadly. We expect bigger better games, but from the SAME dev cycle we expected for games 15 years ago. The result is always a product nowhere near as polished as we'd like, and results in a culture of Day One Patches and Patching to fix issues continually.
I've lost count of the number of products and publishers who struggle with this. Bethesda are by no means exclusive in this.
Skyrim ..... is one of those games that is not finished, and it is a shame because the game is pretty good.
But I'd disagree with that...
It IS a finished product. Just not as polished and thoroughly debugged as we'd like. There is no progress issue which repeats 100%, or cannot be fixed by returning to an earlier save. There are glitches, but if it were 'not finished' it would never have passed certification at Sony or Microsoft.
Your point is valid. But your terminology is incoprrect for what you are trying to express.
I've started about four times and each time I lose the urge to play because of all errors and bugs.
Just go back to an earlier save if you have a progress issue. If by bug you mean 'aesthetical or design choice which I do not like' that's a different kettle of fish, of course.
How on earth developers have the nerve to release the kind of product on the market?
Because by and large they are GREAT games, and because shareholders and publishers insist on releasing every game in a specific window. See how many games comanies like EA release per month? Ifyou want your product to sell you've got to pick a week of the month where a larger publisher won't minimise your sales. That, at the end of the day, is what drives modern games sales sadly.
5 years in development and the end result is a joke from a technical point of view
Textures, shadows, light and other factors are poorly optimized and shadows OMG those are the ones ugliest I've seen in many years.
Sadly, the optimising stage of development for most developers is the one which gets cut the most, due to deadlines. It's not like the good old days of 'release when we're happy with it'. Of course, if we did go back to that NO game would ever come out...

And in order to be able to play reasonably well you have to change ini.files, it is not the developer's job to make sure that the code is right?
Specifically what do you feel you need to change, out of curiousity?
First, you pay $ 60 and then you have to wait for updates in order to play, it's like buying a car and wait for the tires.
Welcome to mainstream videogame publishing! Where nobody gets what they want.

I would not even think of quests that are completely broken and to cope with the quest you have to end it with console commands .... Are you kidding me BETHESDA seriously.
There is no quest which is completely broken. There are quests where something odd happens, or something goes wrong, but almost never a 100% repeatable issue that ALWAYS occurs. Of course if you've found something specific always post a bug up in the support forum. You never know it might get fixed in a later patch.
I no longer dares to explore because I'm afraid to destroy the quest line.me to ignore all errors and play or should I wait 6 months or more until the game is playable?
I'll admit that very much is how I feel about things at moment, mind. And I agree that it is frustrating.
If I find something I post it in the support forum. It's all I can do. It's the same with a dozen games I own. It's the danger of open world games really.