With battery drills there are three separate components,
From memory,
the battery
the trigger
the chuck
I have been told that some large buying companies who have a unit on every industrial unit in every town will go to the likes of the manufacturer and say, we would like to buy 60,000 sets of these. They use the lowest grade of each of the above so they can knock them out at a super price. I have been told of one manufacturer who does it. I was told that the likes of Makita and bosch don't. But no evidence either way.
The reason they do it I suppose is that most people will use them for light use so only a few will come back with issues.
So here is the thing, if you buy it from said store and it comes cheap with an2 or even 3 year warranty then, buy it, the warranty will cover it. If you are going to be using it hard then spend the extra and buy top quality.
i will refer back to my chain saw. I bought a draper, used it for 4 years, um, maybe 5, now it has stopped working, I will sell it on evil bay. Maybe get £20 as a non runner. Total cost, £100 minus £20. £80 all in. I have had my money out of it, I could buy one of the higher end items and have it serviced every year but, for me, £80 for someone to look at it then charge me more to do any work, just not worth it.