Do all mutual fund schemes produce the same returns in the long run?

All funds do not give the same returns. This depends on the Type of Fund, and the Channel you buy it from.

1. Channel: If you go through a broker or an app that does not offer “Direct Plans” of Mutual Funds, then you will lost 40% more gain on your total portfolio. That is because the 1% to 1.5% commission that the broker takes adds upto 40% over the long run. Always go for Direct Plan Mutual Funds. Choose an online platform that makes it easy. Jama.co.in is one [Disclosure: I am with Jama]
2. Type of Fund: Mutual Funds invest either in stocks or bonds.
   1. In general stocks give higher return over a longer period.
   2. Bonds are more predictable and give stable returns, but lesser than stocks.

In general, higher the risk, higher the return over a long enough time period. This applies to debt or bond funds too. You can easily fund the various sub categories and find the returns expectations.