I really haven't been smothered by checkups every few minutes. When the servers are really good, they can anticipate when you need something by simply looking at you and your table. They know when your drink is empty and when you want it filled. A server should rarely need to ask that stuff verbally. If they are continually checking up, they are inexperienced or insecure.
After I make my order, the server will usually try and take my menu. Lately I've said "I'd like to hold on to this" and they love when you do that! I don't always follow-up with another order, but sometimes I just need an extra side dish, or a dessert.
I've had that overstaffed experience, too. There are one or two small chains around here that employ 3x as many servers as they need. And their rooms are always 1/5th full or less. So the moment I walk in, there are 3-4 people greeting me and escorting me to a table, before I can even pull off my hat and gloves. In the same place, while they don't appear to do "team service" I would meet one waitress, and then get fobbed off on another guy for no stated reason. If they are sharing tips, a lot of slices to that pie.
You could ask for the salt or ketchup when the meal arrives.
Also Europeans are not, I think, accustomed to asking for salt, or ketchup, on already seasoned food. So your request is actually unusual.
For ketchup, I'm afraid you'll need to stay in the US.
That’s a perfectly valid reason for complaining, then. Politely, of course, but the chef might use the feedback.
One thing is true though, I never ever had to add salt in restaurant in past 25 years, one can ask for pepper/olive oil/etc but salt? They often use too much of it to enhance taste ie in sauces. Maybe get your kidneys and heart checked with such refined palate.
A chef forgetting to add salt sounds like a photographer forgetting to use a camera.
I would expect to find salt, pepper and mustard on the table in a decent restaurant, in my corner of Europe. Not ketchup, though, except in a cheap burger place.
Not all us Americans are, either. The only time I can remember asking for such things is when the server forgot to provide ketchup for some fries.
If a restaurant doesn't season the food adequately for me, I'm not going to fix it at the table. I'll just factor that in the next time I decide where to eat.
Also, the vast majority of restaurants I've been to use far too much salt during cooking anyway.
The feeling I get from those experiences is that I'm being rushed to clear the table, not that the service is great and always there to help me.