I don’t understand this - didn’t Intel have a working cellular modem chip before Apple bought that segment of the businesS? Sure, it wasn’t good, and Intel probably saw that it was going to be difficult but with the amount of money Apple invested in this, starting with a working product, how so they not have a working product?
I think you answered your own question. It wasn’t good. Apple isn’t willing to sacrifice battery life since it has been one of their biggest selling points on the iPhone for years. As far as why they haven’t figured it out yet. It is probably pretty difficult. Intel spent tons of money on it and couldn’t succeed. A chip maker gave up. That should tell you how difficult the process is. The 5G modem industry is basically a monopoly so there are a ton of companies that would be trying if it were easy to do.
Loads of companies make the tower equipment, including Huawei, Cisco, Nokia... in those cases, size, cool running and low power draw aren't as important. Apple gives no shits about that part of the industry.
Power draw for cellular tower equipment has become a major concern and product differentiator for mobile operators. I work in telco sector.
AFAIK Apple develops their modem in Germany. The initial effort to get into this market is tremendous. After that it’s incremental improvements, but you must start somewhere.
I can’t find any reviews of the chip itself, just announcements. It is too early to say they succeeded. Also intel did make a 5G modem for phones. It just was a couple of years behind Qualcomm’s chip. There is a good chance that Huawei’s 5G chip will be the same. If you look at the phone they are going to sell with the new 5G chip, it has a main processor that is performing at the standards of two years ago. The 5G modem could be the same way. Furthermore, Huawei could be breaking patents and be fine as long as the phone isn’t sold outside of China. The main difference is that Apple doesn’t want to put a worse 5G modem in their products and can’t pretend that patents don’t exist.