Non-malevolent synonym of envy

The noun covetousness has the idea of wanting what someone else has (not just something similar to it), without malevolent intent.

Covet verb Yearn to possess (something, especially something belonging to another) - ODO

The words yearning, desire, etc convey the idea of wanting something, but don't necessarily carry the idea that someone else has one.

A noun that comes close to both senses of wanting something and referencing something external is aspiration:

Aspire verb Direct one’s hopes or ambitions towards achieving something - ODO

Unfortunately, it tends to be applicable only to greater degrees of intangible qualities. For example:

i aspire to reach his level of coolness - crybaby

emulate -- From Merriam Webster

to try to be like (someone or something you admire)

to strive to equal or excel

In the case you describe, you would want to emulate the qualities that made the person successful and thus able to have the life that you admire and wish for yourself. If you succeed, you take nothing away from the person you emulate.

Keeping up with the Joneses

"Keeping up with the Joneses" is an idiom in many parts of the English-speaking world referring to the comparison to one's neighbor as a benchmark for social class or the accumulation of material goods. To fail to "keep up with the Joneses" is perceived as demonstrating socio-economic or cultural inferiority.

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There is nothing malevolent here. To some it's not even negative. Though it does go against some less materialistic philosophies.

Consider, yen

yen (yĕn)

n.

A strong desire or inclination; a yearning or craving.

intr.v. yenned, yen·ning, yens

To have a strong desire or inclination; yearn.

[Cantonese jyun6, hope, wish, from Middle Chinese ŋyan` (also the source of Mandarin yuàn).] American Heritage® Dictionary