Yeah the 128TI is cheaper because the base spec is lower.
Which of course comes back to whether if you had to pay for the things on the GTI whether you would...
In the past VW Germany used to sell the GTI very bare and let you add what you wanted - not something VW UK have ever done. A UK performance Mk7 or Mk8 is pretty loaded to start with vs most other "base spec" cars.
BMW have always tried to sucker their customers into paying for expensive options...
Apart from anything else I have previously said about my day with a 128TI, I'd add that I never felt like it was much fun. My Mk8 GTI is a lot more fun handling, with the zero understeer allowing you to really throw it round the corners with laser precision. The BMW just felt like it handled without any joy - despite what BMW tell you about having engineered it to be fun.
Most of the track based reviews tell you the same - but more extreme. Even on the road as a mediocre driver I can definitely say I can tell the difference.
Actually thought the base spec on the 128Ti was very generous, all the stuff really need was standard, and only added £1000 of options, which is lowest ever spent on any car making it car want, privacy glass, electric lumbar support, split folding rear seats (gives arm rest) and park assist (to get camera) and a late addition of heated steering wheel for £150 as Exonian stated life was simply not worth it without one
£35,150 was total, and that's £2250 cheaper than what was paid for the TCR in 2019
Did test drive the 128Ti way back at start of year, and this is jumping out of the TCR, straight into the 128Ti and it felt quite lively in the hand, and the ride was not something that noticed on very familiar roads that travel regularly, and as got out, it felt like had a really good experience when add in the quality of the cabin.
The 128Ti has its own unique set up, and does seem, from looking around on varying forums that its not comparable to other 1 series models, due to that uniqueness.
Its just about to get a 3 year saturation test as a daily, so we shall if my snapshot experience equates to the long term reality, it has big boots to fill in the TCR, which to date is best car personally driven.