Not sure a short summary will cut it.

They had no competition for a long period and ended up with an accountant CEO that caused their R&D to stagnate massively. They had a ton of struggling and failing to deliver all in most areas, and they wombled about releasing CPU generations with ~4% performance uplifts, probably saving a few bucks in the process.

AMD turned back up again with Ryzen and Epyc models that were pretty good and and an impressive pace of improvement ( like ~14% generational uplifts ) that caused them such a fright that they figured out they had to ditch the accountant.

Pat Gelsinger was asked to step up as CEO and fix that mess. They axed some obvious defective folks in their structure and rushed about to release 12th generation products with decent gains by cranking the power levels of the CPUs to absurd levels, this was risky and it kind of looks like they are being bit with it now.

Server CPU sales are way down because they are just plain uncompetitive. They have missed out on the chunk of money they could have got from the AI bubble because they never had a good GPU architecture they could leverage over to use. They have been shutting down unprofitable and troublesome divisions like the Optane storage and NUC divisions to try and save money, but they are in a bad way.

The class actions mentioned elsewhere in the thread are probably coming because the rush to make incremental improvements to 13th generation and 14th generation CPU’s resulted in issues with power levels and other problems that seem to be causing those CPU’s to crash and sometimes fail altogether.