Its quite common to bring back a player whose loan has not been ideal despite the quality of the player - which accurately describes Scarlett loan at Oxford where despite lack of game time he was joint equal top scorer for the season to date with 4 or 5 goals alongside about 3 or 4 other players last month.
I think Allie Gold and POK leapt to the conclusion he would be re-loaned out as Lankshear has done ok as a back up striker (although not played enough) and the assumption was he would stay at Spurs - and not enough game time for both.
Ange has looked at the 2 of them and made the perfectly rationale choice that Scarlett after loans for 2 years is much more experienced in playing mens football now (over 90 appearances - albeit only maybe 20 or 30 starts mostly L1 and Championship) including about 18 for Spurs in all competitions and has scored 10 goals in L1 or Championship, plus Scarlett has been quite prolific in England age groups including E u21's.
Scarlett is a year or so older than Lankshear and physically is more muscular - although Lankshear is now quite a unit, Scarlett is close to a full grown man.
So whilst I think Lankshear has huge potential, his experience of playing mens football is very modest - maybe 10 matches for Spurs first team and in u21's playing in EFL Trophy v L1 and L2 sides.
Roll forward 2 years and its not clear whether Scarlett or Lankshear will look the better striker, but right now, Ange has bet on the more experienced Scarlett, and its a rationale decision - even though I hoped Lankshear would get more playing time at Spurs this season.