Considerable experimental and theoretical research has been dedicated to understanding the connection between the biochemical activity of cells and their mechanical environment. This is exemplified by the common structures of developing epithelial cells between various species and the decay of cell population growth rate over time. We study these two phenomena in a system of simulated cells with identical mechanical properties, and growth factors in both epithelial and 3D configurations embedded in viscous fluid. We demonstrate that the increase in the density of cellular systems and the consequential crowding of cells by their neighbors are crucial factors in causing the decay of tissue growth rate. We also show that tissue structure can be reproduced by a purely mechanical model with a more faithful treatment of inter-membrane interactions. Finally, we also show that, assuming all other factors constant, growth, and final structure depends on inter-membrane and medium friction coefficients. Of these two, the latter has a stronger influence on slowing down growth and disrupting structure.