Is MBA worth its cost?

I recently ran a very simple analysis to understand if MBA is really worth its cost. I made some assumptions to make the analysis very simple. Here's what I did:

I took two cases - liberal and conservative case

Case 1: Liberal
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MBA starting salary: $120k
Yearly raise: 10%
Annual Tax: 35%

Year 1 MBA cost: -$50000
Year 1 Opportunity cost: -$50000 (post-tax salary loss)
Year 2 MBA cost: -$50000
Year 2 Opportunity cost: -$50000 (post-tax salary loss)

NO MBA

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Year 1 (NO MBA): +$50000 (post-tax salary)

Yearly raise: 7%

Annual Tax: 35%

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Case 2: conservative
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MBA starting salary: $90k
Yearly raise: 8%
Annual Tax: 35%

Year 1 MBA cost: -$50000
Year 1 Opportunity cost: -$50000 (post-tax salary loss)

Year 2 MBA cost: -$50000
Year 2 Opportunity cost: -$50000 (post-tax salary loss)

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No MBA
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Year 1: +$50000 (post-tax salary)
Yearly raise: 7%
Annual Tax: 35%