There’s been a lot of talk about that, and it’s likely to happen. That 3-4 billion is probably just a rip-and-replace cost, taking into account the fair value of the equipment in 2028, when the 5G renewal cycle will also be approaching in Europe and hardware would be updated anyway. The liberation of market shares in the renewal cycle and 6G is, in my opinion, the big deal, and someone smarter might be able to say how much potential market share/revenue will be freed up in euros. Billions per year in any case.
Huawei has about a 30% market share in mobile in Europe, and that will be partly divided between Ericsson, Nokia, and Samsung. Possibly something extra from fixed networks and/or data centers as well. It will truly be a heyday for owners in 2028-2030 when so many positive things materialize at once. This phasing out of Huawei will, of course, be visible earlier, as operators at this point should no longer buy equipment from them, as the final decision is already expected.