You're basically just listing Doc's strengths and assuming that's enough. Kirby has better top tier MUs, stronger combos, an easier time landing, better ground mobility, a vertical kill throw, and versatility in MUs offered by his ability to copy his opponents. He also has better ledge trapping and edgeguarding.
Oh, and superior defensive capabilities thanks to being really, really small. Add that with being floaty and he SDIs many things for free.
I personally do not agree with half of the statements you're making, and show a lack of knowledge on the character.
Better top tier matchups is highly arguable: Both of them are pretty bad against Rosalina & Sonic, both of them are good against Fox, Doc does decent against Mario & has a respectable Diddy matchup, Kirby does decent against Sheik & has a decent ZSS matchup. Everything else mostly ranges around the doable loss, at least for the Top 11. So it's fairly even.
Strong combos is not something i agree with, when you consider the character's combo game overall. Kirby may have stronger combos on the fastfallers, but Doc's advantage state is the more consistent one out there, with such things as Dthrow USmash at low% on most charas, and Dthrow Rar Bair x2 at mid%. Landing Uair confirms into grab starting at midlow%, late nair starts some low% combos when used as a landing mixup, sourspot bair can lead into a grab at higher%, and so on. Doc has a very consistent advantage state on top of having a very deep mixup game that can truly be fatal at times.
Easier time landing, i'm not exactly sure how good Kirby's landing is, so i won't state whether or not Doc's landing is better, but improvements have been made on Doc's part that allow the character to land better, most notably, the user of Wavebounce Cape to reverse our momentum. Cape is among the best tools of Doc and is usually non commital, so using it in mid air can save you from some deadly situations. Still, Doc's landing isn't the best, i'd agree wih that, but it has improved over time.
Better ledge trapping is something i'm not sure either. Doc's kit is filled with tools that are very much capable of trapping at the ledge, most notably, Nair makes for a pretty efficient tool against Regular & Offensive getup, since you'll be getting the late hit most of the time, Tornado's mobility allows you to cover roll & regular getup and send them pretty far thanks to the move's strong initial knockback, UpSmash can be used to catch jump airdodge getup, trade with some jump attack getup, as well as against regular getup. Finally, our strong oos game, most notably with UpB. So yeah, our ledge trapping game is plentiful.
On to edgeguard game now, where i'd believe the characters are quite close in terms of capabilities of offstage gimping. Their mobility hold them back from doing much against high recoveries, however, they both shine against low recoveries. Doc's Tornado long lasting hitbox can be used to your advantage to trap airdodges, which is very strong. Using Pills just near ledge to snipe people's jump and preventing them from recovering is also a fairly efficient strategy. Finally, trading the low recoveries with Doc's Dair will lead to a semi spike, similar to what you'd see with Luigi's Cyclone. Characters like Mario can't recover from that.
Overall, i believe that both characters would fullfill the same ideal role in the metagame, with little to no solo viability but niches against different kinds of characters each. Thus, they're about as viable. But if you had a knife close to my neck and ask me who's better, i would say Doc because of his consistency and efficiency in some areas that allow him not only to shine against some brawlers & zoners, but also to be able to be quite a fearsome character for most opponents in the hands of a good player.