Power is what moves the aircraft foreward, friction is what holds it back . you must increase power a lot more to get it rolling than you need to maintain that speed! Therefore you can control speed with throttle, – but this is a “hunt” and see what is best “juggle”. Therefore you can apply brakes slowly to maintain the speed you want, as you “zero in” on the proper power setting. You will aslo find that the faster the plane is moving the smaller increment of RPM change is required (Throttle controls rpms). Once you get the plane rolling good, – you have inertia on your side, – but you also have it aginst you when wanting to slow down (because inertia wants to make “slow” changes in speed “mass will continue to propel plane some distance even with power shut off! However in air “altitude” will be down (to keep speed up).

This is also true in air to some extent, but when flying,– power is regulated different if you have a “controllable pitch prop”. In flight, you can control RPMs with “prop pitch”, – and manifold pressure with throttle! This is a “interplay” adjustment between the two! But in the air you control your speed by the “pitch of aircraft” up or down pitch under power also controls speed). The “power” now maintains your altitude, — as well as controlling speed (more evident going down – than up!) Note that the plane can still maintain speed going down – even with engine shut off,—this will depend on how fast you are going down (pitch of plane).

Your job as pilot is to manage power (thrust), and drag (friction) to get results you need! Of course you also want to navigate so that you can find place where you are going, maintain your altitude, communicate so that you don’t hit anybody, – or get hit. Keep sharp eye out for other aircfraft for same reason. (and keep airplane right-side-up most of the time) also keep track of fuel left, and fuel consumption rate (to make sure you have enough to get to airport).. Otherwise there isn’t much to do when you are flying!
Better to leave auto pilot “off” when taxiing! George (the auto-pilot) can’t see what is going on in front of you! Autopilot is maintaining engine rpms, – not ground speed!

NOTE: Pilots get old by being cautious and careful!

A jet engine produces thrust even at idle power, unlike a propeller.

So at light weights the plane will be accelerating even at idle power, so the most brake-friendly technique is to allow speed to build up to about 25 knots then make one smooth brake application to bring the speed down to about 10-12 then let it go again.

Unless you work for a US commuter airline, in which case taxying at 40 knots seems normal!

If you are talking about a small aircraft, it’s b/c it doesnt’ take much to move that “small” aircraft. Just back off on the throttle, don’t ride the brakes….. just like every other part of flight, it’s a touch that you have to get used to.