But these jobs just didn't exist(unless you count full time maids for example), so it doesn't make sense to talk about job security or whether they were contractors or not.

I'm not sure we have enough data yet to say whether the people doing these jobs previously did or didn't have better paying or more secure jobs. Anecdotally, there are many people whose income and job security have severely declined, and who been relegated to low payed variable-workforce service jobs. I don't know to what extent people like that are represented among the taskrabbit-type service workers.