I still don´t have a Switch, I´m waiting for something huge (of my taste) to be released hopefully this year or at least announced :)
I´m talking about:
-A main Pokemon,
-Yokai Watch,
-Golden Sun,
-Final Fantasy V & VI remakes,
-Bravely Third and
-Warioland.

Also I have a huge backlog of 3DS games and also waiting for
-The Alliance Alive,
-Yokai Watch 3, Busters and Sangokushi, and
-Dragon Quest XI

so that´s another reason u.u

Quite a few things still need to happen I think. The system by it's very nature doesn't appeal to large segments of the 3DS player base.

It's considerably less portable, and doesn't yet feature the franchises that brought in and maintained most of the female players, being Pokémon, Animal Crossing, and surprisingly Fire Emblem.

It also doesn't feature any of the experimental freebies that the 3DS was famous for.

"When will 3DS owners migrate to Switch, and in what capacity?"

When the price to entry is right.... Switch just too expensive atm, to be viewed as a handheld.

I could see Pokemon + 199$ pricetag = huge spikes in sales for Switch.

Its just a question of if nintendo will ever be willing to sell it at break even point? 199$ shouldnt be impossible for them.

The price of the Switch will be the major reason why people will hold off on the Switch when upgrading from the 3DS

More definitely will over time, because 3DS games will eventually move over to the Switch

It's already happening, it's an ongoing process, as usual. There will be big influxes with games like Pokémon, Animal Crossing, Super Smash Bros., 2D Mario, etc.

Price isn't a hurdle for a lot of people. Switch library is better than the 3DS, people realize that.