Yup, the issue is that Intel had literal complete dominance in servers, even taking 1.3% is actually a monumental step. It means that with no in place working plan to validate/certify servers companies still took not of EPYC and started that work. EPYC 2 also adds to the belief that server guys should bother with AMD. EPYC 1 alone was a single chip and if AMD couldn't execute another step fairly quickly it would be seen as a flash in the pan. EPYC 1 is showing off Zen to the server market and they were absolutely interested, EPYC 2 is the thing that makes the server guys commit, which is why as EPYC 2 taped out a whole bunch of server makers and companies who buy servers got a whole lot more interested.
With EPYC 1 server guys mostly validated and worked on certification and building their own computers after it launched. With EPYC 2 they are doing much of this work during the sampling phase and concurrently with AMD also doing this stage of work. So with EPYC 1 there is a ~1 year lag between launch and the servers coming out, with EPYC 2 it should be possible that a few servers launch alongside the EPYC 2 launch and a lot more within the first few months. With the same socket and similarity of the platform making the second lot of servers will also be much much less work.
There is also issues in terms of volume, with Glofo it's hard to say how much production AMD were using but Glofo had other customers also and AMD was making it's whole line up at Glofo. With TSMC able to be involved due to the wafer agreement change it opens up vastly more volume for AMD.
1.3% is a much much bigger step, in the same way the saying goes that the first million is the hardest, once you get a foothold and once you get people actually building and validating servers and it's actually selling it's easier to convince the same company to make 5 different types of servers and then see them all selling the next time. THink of it like this, new product comes along, committing to build each specific server build might cost a few million, a bunch of work and a commitment to support that server for multiple years but at that time you don't even know if people will buy it because it's a new player. So you wait for the chips to launch, you build one box to limit exposure and dip your toe in the water of the market and see if anyone bites. When those servers sell easily (as I'm under the impression they are) you decide to build 10 different server configurations. You already know demand is there, you know you can sell them and you've been convinced. A year from now when those 10 different configs are available and knowing it will actually be the far better product than the competition this time around, you have no worry they'll fly off the shelves.