Our actions: a mirage or effective

Devarim 8 beseeches klal yisroel not to forget who is really behind their blessings, ending with:  

(יד) וְרָם לְבָבֶךָ וְשָׁכַחְתָּ אֶת י"י אֱלֹהֶיךָ הַמּוֹצִיאֲךָ מֵאֶרֶץ מִצְרַיִם מִבֵּית עֲבָדִים. (טו) הַמּוֹלִיכְךָ בַּמִּדְבָּר הַגָּדֹל וְהַנּוֹרָא נָחָשׁ שָׂרָף וְעַקְרָב וְצִמָּאוֹן אֲשֶׁר אֵין מָיִם הַמּוֹצִיא לְךָ מַיִם מִצּוּר הַחַלָּמִישׁ. (טז) הַמַּאֲכִלְךָ מָן בַּמִּדְבָּר אֲשֶׁר לֹא יָדְעוּן אֲבֹתֶיךָ לְמַעַן עַנֹּתְךָ וּלְמַעַן נַסֹּתֶךָ לְהֵיטִבְךָ בְּאַחֲרִיתֶךָ. (יז) וְאָמַרְתָּ בִּלְבָבֶךָ כֹּחִי וְעֹצֶם יָדִי עָשָׂה לִי אֶת הַחַיִל הַזֶּה. (יח) וְזָכַרְתָּ אֶת י"י אֱלֹהֶיךָ כִּי הוּא הַנֹּתֵן לְךָ כֹּחַ לַעֲשׂוֹת חָיִל לְמַעַן הָקִים אֶת בְּרִיתוֹ אֲשֶׁר נִשְׁבַּע לַאֲבֹתֶיךָ כַּיּוֹם הַזֶּה. (יט) וְהָיָה אִם שָׁכֹחַ תִּשְׁכַּח אֶת י"י אֱלֹהֶיךָ וְהָלַכְתָּ אַחֲרֵי אֱלֹהִים אֲחֵרִים וַעֲבַדְתָּם וְהִשְׁתַּחֲוִיתָ לָהֶם הַעִדֹתִי בָכֶם הַיּוֹם כִּי אָבֹד תֹּאבֵדוּן. (כ) כַּגּוֹיִם אֲשֶׁר י"י מַאֲבִיד מִפְּנֵיכֶם כֵּן תֹּאבֵדוּן עֵקֶב לֹא תִשְׁמְעוּן בְּקוֹל י"י אֱלֹהֵיכֶם.

In this article I'd like to focus on pesukim 17 and 18, quite well known and oft quoted. 

What do they mean practically? 

Are they making the argument that our actions are incapable of producing any real world effects, with our efforts merely a smokescreen for the omnipotent divine actor, or, alternatively, do they recognize human industry and our ability to be productive, with the exhortation that we not forget who gifts us the tools and skills necessary for productivity.

This seems to be a point a contention, with Ran (in his Derashos) coming down firmly on the latter side, and Ramchal (eg in Mesilas Yesharim and Da'as Tevunos, hat tip to my friend and erstwhile chavrusa, R Zvi Katz, for the second source) seemingly espousing the former.

It's a fundamental theological question with real world consequences. 

If one subscribes to Ramchals view, one isn't incentivized to work all that hard, pursue higher education, or engage in other efforts that typically correlate with better life circumstances, as they aren't seen as causing them, but merely (and bewilderingly) correlated. 

Whereas if one adopts Ran's conception, one does have the impetus to do all that is in one's capacity to better one's life circumstances, particularly economic, as our actions are seen as causing and producing real material benefit, with results commensurate with and in proportion to our effort and preparation. 

Relatedly, see here for a discussion about if we can intentionally harm other people even if they don't deserve it