> It is insanely so. x100 more difficult. If it wasn't, someone else would have landed an orbital rocket by now, when they landed a suborbital in the 90s.

It's not insanely difficult, it just hasn't been tried very often. Every program that tried VTVL rocket landing has succeeded (DC-XA, Blue Origin, SpaceX). It just hasn't been tried much. The reason it hasn't been tried much is because reuse hasn't been prioritized or done very pragmatically. Prior to the 2000s most RLV development focused on unrealistic designs such as the Shuttle or SSTOs, not on simple two stage launchers with booster reuse. More so, there hasn't been much competition in the launch vehicle space until the 2000s, for a variety of reasons, so extreme cost competitiveness wasn't a major factor until then.

Additionally, there are many natural optimizations that have traditionally been made with expendable launchers which deoptimize them for booster reuse. Expendable launchers tend to have simpler, lower cost first stages with only a few engines (Delta IV, Atlas V, and Ariane 5 only have one), while the majority of the cost and complexity is pushed into the upper stage. This makes first stage reuse much harder, especially in the VTVL configuration (it's very difficult to throttle down a single huge engine vs. simply turning off extra engines) and it makes it useless, as you end up simply saving the cost of expending the cheapest part of the rocket. You have to go into two stage launch vehicle design while planning ahead for VTVL first stage reuse to actually make it worthwhile. The genius of SpaceX was that they made very pragmatic design decisions that aimed at reusability straight out of the gate, and they figured out how to do the R&D for reuse within the context of paying commercial customer flights, making use of "thrown away" hardware that created the equivalent of a billion dollar funding stream. But much of that can be copied by anyone paying attention. SpaceX may have some degree of "secret sauce" that drives their success, but simply achieving VTVL reusable rockets is not it alone.