Because lives gained is directly tied to how many times you die, the less skilled a player is, the fewer resources the game gives you. It has the ironic conclusion where the only way to get the maximum amount of lives in SA is to prove you don't need any of them.
I know what you're talking about, but if we bring scoring into the topic, it does bring in an extra layer of what the extra lives are actually used for. Scoring in SA you need to be able to suicide for points early on (and later on even), yet still balance it enough to keep your maximum by Utsuho. All the lives you gain early on are used up on Parsee,and then you need to gradually build back up.
When you're simply playing for survival (as you described), the net lives you have isn't directly proportional to how well you do. It could be said then, that the usual complaint of "the game showers you with lives" is invalid. It also means that the difficulty of the game isn't directly proportional to your skill, either. Throughout the course of the game, at best you have 13 lives. In the worst case, you have to die 10 times on life-giving patterns and then one more death in order to game over at SubSun (13-(10/5)= 11, 11-(10+1)=0).
Now that's what the problem was with UFO, the way to get extra lives and bombs was separate from the core gameplay. You had to focus on 2 things at the same time. Though not that it was a bad idea, it created a different kind of difficulty.
UFO has this odd thing going where because you had to focus on two things at the same time, you would die more often. However, that's really only true as you're learning the game; you don't know what UFOs spawn where, and you don't know appropriate times to summon one. The curious thing is that in order to make the game "easier", the players have a tendency to map themselves UFO routes and then enact the same ones every single time (most commonly, to get all the reds). Because it's something you memorize, people can concentrate on the bullets and easily get the UFOs. However, memorization often leads to laziness, and without enough stimulating you, you lose concentration and die. And even still, in most runs, you aren't going to get a perfect route. Something will screw up the route, and then suddenly people are in a panic because they want to get back into their route and they don't know how, so you try bolder moves to get the UFOs, you lose concentration, and die. In general, the more people try to group UFOs together as a route, the more often they will fail. This is why Lunatics in particular focus more on the concept of getting UFOs at a particular point, instead of getting specific UFOs. For stages until 5, mostly you'll want to gather reds and later gather greens, but the methods of which you get them can vary wildly throughout different runs since you don't convince yourself to stick to a predetermined route. This makes for variety, which increases attention and improves your ability to ad lib, which ultimately leads to less deaths and more net lives/bombs. In these runs, there are often rainbow UFOs to adjust your stock, which also have the added bonus of exchanging points for power items, which also helps the whole problem of "you only get .07 power back when you die".