Then the perfectly qualified PMs start from square one again.
IMHO it's an essential skill for a PM to familiarize him/herself with a new domain in short time. It also offers cross-pollination / the chance to do things different. Imagine Steve Jobs coming from a pure IT background instead of liberal arts / calligraphy -> Apple wouldn't have been so different any more.
> Then the perfectly qualified PMs start from square one again.
Exactly the same point holds for programmers: what if (say, by becoming acquired) a company has to switch from being a, say, a Deno/Vue.js shop to becoming a Java shop? Exactly.
So the answer is: don't do such radical changes in the product portfolio and way of doing work if you don't want the employees to more or less to start from square one again.
They had the ability to learn technical things once, then they can do it again. (In a short time? Not so easy to find out until after you've hired them, in any case?)
The insult to that is also "no changelog". I hate the generic "we try to make it better, but ain't telling you what". So at this point it's a gamble whether I want to update or not, so I don't.
Also for Spotify, perhaps it's time to allow a pool of 1000 (?) volunteers from each language to help you rewrite titles, names, etc. in the local languages. I'm happy for the latin alphabet, but do make a "local language" field and then let the users see THAT instead of the common if they choose to.
PM for retail company did long stints in merchandising at Costco
PM for spreadsheet company was a former banking analyst
Most companies hire under qualified generalist PMs who have to learn everything about their market from scratch; it’s very challenging and prone to outright failure.
Hire fewer PMs, and make sure they bring a key skill to the table. Let Microsoft and Google train the juniors.