It took a while, but the lack of in-person Standard format organized play has finally begun to catch up to WotC's sales of sealed product as Pokemon TCG dethroned Magic: The Gathering from the top three slots of the TCGPlayer Top 25 Sealed TCG Product list for January 2021 (see "TCGplayer Top 25 Sealed TCG Products - January 2021"). On the November list (see "Top 25 Sealed TCG Products – November 2020") and the December list (see "TCGplayer Top 25 Sealed TCG Products – December 2020"), Magic was firmly in charge, commanding the top two slots on the list. Then, in January, Charizard and company torched Magic with Pokemon TCG products claiming four of the top five top slots.
Several factors contributed to this changing of the guard over the short term. As mentioned previously, Standard is only being played on MTG Arena or in ill-advised, non-sanctioned underground Magic tournaments. If the only place a player can compete in sanctioned events is online, there is little to no reason to accumulate play sets of cards for the Standard format. This limits the Magic sealed product customer base to collectors, investors, and casual EDH players, thus impacting sales.
Another issue, this time with the Kaldheim product itself, is that it boasts only four cards with different titles that can be pulled from a Draft Booster Box which are worth more than $10 on the singles market (excluding foil versions of these cards). The initial value for this set is simply lacking when compared to past Standard sets, and players and collectors are buying less booster boxes as a result. The biggest factor, though, for Magic moving down the list is still that Pokemon TCG is still in the middle of a Golden Age of sky-rocketing single card prices spurred on by collector enthusiasm (see "Rolling for Initiative -- Pokemon, the Halo Effect").
As for other notable takeaways from the January data, Yu-Gi-Oh! and Flesh and Blood TCG products moved down or off the list. Blazing Vortex, the latest Yu-Gi-Oh! set, landed in the eighth spot, but according to ICv2 columnist Scott Thorne, the solicitation of this set to retailers could've been more aggressive (see "Rolling for Initiative -- The Lessons of 'Kaldheim' Prerelease Events"). Flesh and Blood TCG's being bumped off the January list can attributed to no new product releases since November. They are clearly gearing up for an April release of Monarch (see "Legend Story Studios Unveils the Next 'Flesh and Blood TCG' Set") and a middle of the year release of Crucible of War Unlimited.