Switch just isn't powerful enough to run a lot of 3rd party games. Considering that, the support was great. It's hard to name a 3rd party multiplat in 2017, that could run on Switch, but hasn't been brought over.
I'm surprised you're saying this, I don't think anyone has ever argued that the Switch started with good third party support ... the first month it released it was so dry that basically most of the high profile indies were either games that were so old/sold so much they weren't relevant or were games that Nintendo themselves published.
Unless you mean like, by the end of 2017. Then I can kind of understand that position more and even somewhat agree (not sure I'd go as far as to say "strong", but Doom, Skyrim, and Fifa was pretty good).